Periurban Streetscape—Vernacular Front Gardens and Their Potential to Provide Ecosystem Services: A Case Study of Warsaw, Poland

Abstract

At the time of reflection on green justice, when the role of public green spaces is increasing, it is worth paying attention to vernacular greenery, especially in single-family residential areas on city outskirts which property owners arrange in front parts of plots. The paper’s aim is to show that vernacular front gardens (VFG) can act as missing public space and at the same time have the attributes of public green space, providing ecosystem services (ES). In order to confirm these assumptions, we carried out a VFG’s attributes inventory and a survey on garden designers. We identified dominating garden features and conducted a cluster analysis of the gardens based on their characteristics. The basis for building periurban streetscape in single-family housing estates is the visual inclusiveness of VFGs. They provide all the ES groups, playing representational, natural and recreational roles as well as serving as locations of edible plants production. Streets in residential sites, thanks to VFG, can be treated as real green public spaces creating a type of green area accessible not only to owners but also to pedestrian eyes. We conclude that our results can be valuable for city planning but also for the professional garden designers.

1. Introduction

1.1. The Research Background

Over some recent years, the role of urban greenery has significantly increased. Green areas are important not only due to the climate crisis but also for sanitary comfort. In the growing significance of greenery in maintaining quality of living environment in cities with persistent tendency of urban sprawl [1,2], the role of single-family housing and private gardens attached to them seems to be underestimated. Although research is known about their crucial effect on reducing psychotropic prescribing in people suffering from a spectrum of depression and mental disorders [3], private gardens are marginalised as an effective urban green space due to their exclusivity. Private plots with gardens constitute 11.5% of the area of the Warsaw agglomeration [4]. Compared to Warsaw’s public parks and squares, it is over five times more [5]. For comparison, the garden area in Stockholm is 16%, and in the UK cities 22–27% [6,7].

The importance of garden nature in the environment is undeniable. The benefits for ecosystems and biodiversity are measurable in the case of home gardens [8,9,10]. Together with adjacent urban green spaces, undeveloped and open spaces, they form green complexes important to the ecology of urban landscape [11].

There are many methods of walking comfort research, especially identifying walking environment [12,13,14]. Several microenvironmental audit tools are widely applied in international studies such as MAPS, PEDS or SPACE [15,16,17]. However, the value of private gardens in building the image of local landscape has been hardly studied [18,19]. Although the concept of using private plots as public space is also rarely referred [20,21], we can recall the idea of landscape cores [22], i.e., corridors of public spaces through which users move while perceiving landscape; these are streets with private properties in single-family housing areas. The core of streets with visible front gardens is accessible public space, and vernacular front gardens, if visible from the street, often play the role of the only green space visible to the public in vicinity. The greenery of front gardens is only visually accessible, but still can serve benefits to its users—neighbourhood dwellers and passersby.

A home garden is a very easily accessible handy greenery, providing contact with nature. Front gardens therefore fulfil the conditions of equitable access to public goods, guaranteeing the so-called “green justice” [23,24]. Thus, they may contribute to support the health of the inhabitants and reduce social inequalities [25]. Urbanisation processes also influence rural greenery’s functional and material layer. Usually undervalued as private spaces inaccessible to the wider public, home garden spaces are sometimes the only green areas in neighbourhood, especially in single-family housing areas devoid of public green space [26]. Gardens also fulfil an important function in creating a cultural landscape image in periurban neighbourhoods.

On the city outskirts, public space for social contact is limited to streets in neighborhoods, which give view access to neighbours’ gardens. Therefore, the role of private gardens as urban greenery, providing provisioning and regulating ecosystem services (ES) the same way as public greenery does, cannot be underestimated as mentioned by several authors [8,27,28,29,30].

1.2. What Is the Vernacular Front Garden (VFG)?

A garden, both in semantic and material layers, was described as a vehicle of identity of places and type of greenery which builds the image of inhabited landscape. Thanks to the tradition of using plant species and the forms of composing them, the garden was found as a relatively permanent repository of management traditions in this process [31,32], just like the vernacular structures of rural habitat. Such structures are known as a characteristic structure of home garden, including front garden—an area accompanying the function of presenting the house and possessions [33]. The list of characteristic ornamental plants and crops resulting from the specificity of the peculiar image of VFG use have been also provided [34,35].

Vernacular garden is usually defined as a home garden or part of a private plot traditionally organised (‘designed’), planted and maintained by owners’ families. However, urban greenery in residential sites can also be a carrier of vernacular tradition, having the potential to be organised by inhabitants with various vernacular attributes. They are green elements and place management traditionally applied by inhabitants, e.g., flowerbeds, ornamental greenery decorations, garden furniture, etc. Vernacular gardens are also generally found in cities [36,37,38].

In the history of human habitation, vernacular gardens and architecture have gained distinctive values: features providing provisioning, regulating and cultural ecosystem services (according to Common International Classification of Ecosystem Services—CICES 5.1 and CICES-Be [39,40]. Scientific literature lists emblematic plants and remarkable plant types (e.g., deciduous, conifers, climbers, perennials, plants in containers); “advanced” forms of composition (e.g., rhythmic plantings, row plantings, sculptures, ornamental stones, etc.); and inclusiveness of the view for pedestrians [41,42].

Vernacular gardens reflect the preferences of their owners because they independently choose plants and equipment, combining their own needs, the tradition of arranging inhabited space and contemporary trends set by designers [33,43]. Therefore, the influence of designers’ beliefs and views on vernacular gardens seems obvious, even though they do not design them personally. Furthermore, designers are aware of current needs for environment and landscape (e.g., due to climate change), and there is a growing awareness of private greenery as common infrastructure and ecosystem services provider [44,45,46].

1.3. Ecosystem Services (ES) Provided by Urban Greenery

Although many papers have covered the issue of ecosystem services of housing estates [5,47,48,49], we know little about ES provided by private gardens. The existing research is based on the role of traditional gardens as witnesses to tradition and heritage [50,51], estimating their decorative and representational function [52,53,54]. These functions fall into cultural services [40]; however, this does not complete their list.

VFG can be classified as areas with some potential to provide ecosystem services not only in the whole cultural spectrum, such as physical and intellectual interactions with landscapes; emblematic and spiritual, but also other services described by Millennium Ecosystem Assessment, Common International Classification of Ecosystem Services [39] and CICES-Be [40] such as provisioning and regulation.

Ecosystem services provided by greenery are essential because of their role in regulating local climate and preserving biodiversity similar to other kinds of greenery and producing other food [55]. It is essential, but still not the only role of such a type of greenery. Cultural ecosystem services are crucial, satisfying the needs for territorialism, helping to build place identity and attachment [49,56,57,58]. VFGs have the potential to provide them because of their traditional and familiar image and creating a sense of togetherness and being an indicator of community awareness accompanying participative democracy [59,60].

A good many authors underline the positive influence of gardens for maintaining biodiversity and quality of life, e.g., [11,61]. Research on ecosystem services in vernacular gardens where authors focus on environmental and social values of street greenery stands out [38,62]. However, compared to the abundant studies of potential in delivering ES by different vegetation types, studies of particular attributes of vernacular gardens that influence the delivery of these services are relatively uncommon.

Studies of ES served by multifamily block-of-flats residential areas, allotment gardens and community gardens potential have been widely conducted [55]. However, to our knowledge, the study of private vernacular gardens visually accessible for the public–private front gardens did not occur. By taking into account factors of importance, as for example, size of settlements [25], the values of such gardens can be strengthened through reasonable management. Well-thought-out management of urban green space can also contribute to crime prevention and facilitate safety [63]. Hence, the knowledge of the value of private facilities, which participate in the creation of public spaces in the provision of ecosystem services, can make a valuable contribution to the conscious planning of public green spaces with the participation of private spaces.

Our studies can be valuable for urban planners but also for professional garden designers. We want to show that vernacular front gardens (VFG) can act as missing public space and at the same time have the attributes of public green space, providing ecosystem services (ES), thus contributing to “green justice” in the urban space. The awareness of VGF values could be also important in stimulating and motivating homeowners to thoughtfully build VFGs in a way that contributes to creating a high-quality living environment for residents by the building’s 15 min walkable neighbourhoods [25].

1.4. Aim of the Study and Research Questions

The primary aim of our research was to determine the potential of providing ecosystem services by VFG on private properties in residential sites of terraced, semi-detached and detached houses in Warsaw. The second one was to identify the characteristics of VFGs and to include them in estimating the potential of providing ES in the single-family housing areas and to identify the attributes of VFG that are of importance in the ES delivery. We also wanted to find out if designers (as trendsetters) use design tools to provide ecosystem services in front gardens and if neighbourhood norms play a role in VFG characteristics of individual settlements. To reach the objectives described above, we formulated the following research questions:

1

Do VFG create a landscape of public streets? Are they open and inclusive; do they create street landscape core?

2

Which attributes of VFG providing ecosystem services according to attributes enumerated by literature [39,40] are present in VFG—chosen and preferred by their owners in their VFG development? What are attributes only incidental in VFG?

3

Which ecosystem services provided by VFG are preferred according to the designers?

4

Can distinctive groups of VFG be distinguished?

2. Materials and Methods

2.1. Research Procedure

To achieve our objectives, we designed the research using fieldwork on a selected group of gardens located in the outskirts of Warsaw, and a survey addressed to designers—garden designers. We have chosen Warsaw as it is a big city with typical problems of city sprawl. Dynamic development of city outskirts caused the construction of several single-family housing estates in former rural or green undeveloped areas.

Firstly, we selected representative single-family housing developments for the outskirts of Warsaw—terraced, semi-detached or detached houses. We have picked houses located in residential areas accessible to pedestrians from the outside (unfenced complexes of settlements, without gates and barriers to the street), where the streets leading to the properties are at the same time walking routes used by residents and visitors (Section 2.2). In the second step, we collected the data from the front gardens of the properties selected before, according to a previously prepared inventory form (Section 2.3.1). Simultaneously, a group of garden designers affiliated with the Polish trade association (Association of Landscape Architecture) was surveyed, asking them to complete the survey form we had prepared (Section 2.3.2). In the third step, all the data were analysed using tabular summaries and statistical methods, which are described in detail in Section 2.4. In the end, the findings were discussed and concluded (Figure 1).

2.2. Study Areas Selection

When selecting study areas, in each case, the research subject was a VFG accompanying a private detached, semi-detached or terraced house in its front part (Figure 2 and Figure 3).

Due to the heterogeneity of private gardens in Warsaw’s urban peripheries, the selection of study areas objects was not based only on the presence of a front garden. The following selection criteria were chosen:

• Areas within the administrative boundaries of Warsaw, but on the outskirts of the city, or in loosely built-up areas inside the city, always of a suburban character (single-family housing);
• Stylistically homogeneous buildings (a housing estate)—in the form of terraced houses, semi-detached and detached houses;
• The minimum number of houses (and gardens) in the residential housing estate: three;
• Due to the availability of the estate for passers-by due to the ecosystem services provided—gated communities were not tested;
• Due to the surveyed choices of garden users, only single-family housing was taken into account;
• According to the assessment of the plants age, available data and the assessment of the estate general appearance (of the estate), objects created during the last 20–25 years were taken into account.

Finally, 25 housing estates were selected. Housing types: terraced (248 houses in total, this type is present in 17 housing estates), semi-detached (130 houses in total, this type is present in 12 housing estates), detached (7 houses in total, this type is present in 3 housing estates). Number of developments with only terraced housing: 12, semi-detached only: 7, detached only: 1, mixed (occurrence of terraced housing and semi-detached or terraced, semi-detached and detached in one settlement): 5. The area of the front gardens analysed ranges from 25 to 230 m². In total, we examined n = 385 gardens with a total area of approximately 29,520 m² (Figure 4).

2.3. Methods of Data Collection

2.3.1. Identification of VFG Attributes Delivering ES—Gardens’ Features Inventory

To identify VFG features indicative of delivering ES, the features of gardens related to a given group were classified following CICES-Be [40], considering the features providing provisioning, regulating and cultural ecosystem services (

Table 1. Gardens inventory questionnaire—groups and their description (results widely referred in Section 3.3).

Group	Subgroup	Description
Regulating (Regulation and Maintenance ES)	Trees	Trees, shrubs (improved air quality)
	Surfaces	Plants or water-permeable surfaces and pavements for
	Bees	Bees, butterflies, bird nets, beetle banks for better fruit setting, improving tree propagation, reducing the impact of undesirable invasive species
	Meadows	Hedgerows, vegetation strips, multi-species meadows and turfs
Provisioning	Kitchen gardens	Vegetables, fruits, herbs, wild edible plants; other edible and dyeing plants
	Reservoirs	Well, water feeder, drinking or no potable water for domestic use
Cultural	Plants (as attributes)	Neighbourhood green, shading trees, area of outstanding natural beauty (e.g., rare species, natural smell and noises), attractive and charismatic species, area and species with educational value for physical, social and mental well-being, motoric and creative development of children
	Places	Places to relax and play in the gardens, work on the open air for physical, social, mental, spiritual well- being, inspiration, cognitive development, spiritual development, nature awareness
	Views	Green/blue views from residences for improving mental and/or physical health
	Symbols	Symbolic/emblematic species, cultural heritage, folklore, flagship species for promoting regional identity
Plants	Deciduous trees	Deciduous trees such as lime trees, maples, birches, oaks, etc., fruit trees
	Coniferous trees	Conifers such as pines, spruces, firs, larches of various species and varieties
	Deciduous shrubs	Deciduous shrubs such as spiraeas, barberry, hydrangeas, hedge hornbeams, privet, etc.
	Coniferous shrubs	Coniferous shrubs such as thuja, junipers, shrub pines and spruces of various species and varieties, etc.
	Creepers	Ground cover and creeping plants such as periwinkle, pachysandra, creeping species and varieties of cotoneaster and juniper
	Perennials	Perennials and other flowering plants in flowerbeds
	Potted plants	Ornamental plants in pots and other decorative containers
	Grasses	Lawn or a turf
	Concreted	Solid pavement only
Composition, opening	In front	Flowerbed in front of fence
	No fence	No real or even symbolic fence
	Openwork fence	Transparent fence allowing visual access to the front garden
	Full-fenced	Non-transparent fence preventing visual penetration of the front garden
	Front hedge	Hedge that complements or replaces fence
	Front climber	Climber plant that covers fence
	Good view	Good visibility of front garden from street
	Moderately visible	Moderate visibility of front garden from street
Composition, advancement	Cut	Topiary forms of plants, cut hedges
	Stones	Decorative stones and erratic boulders
	Rhythms	Rhythm in composition of plants
	Sculptures	Sculptures, figurines and a decorative and symbolic nature, rustic decors
	Grafted	Grafted forms of plants (e.g., stave roses)
	Flowerbeds	Advanced composition of more than one flowerbed
	Rows	Trees and/or shrubs arranged in rows

).

In addition, the occurrence of the following elements contributing a peculiar image of VFG was inventoried:

• Inclusiveness of the view: the presence of flowerbeds in front of the fence, no fence, openwork fence, full fence; fence covered by hedge or creeper; good view from the street to the garden, and moderate view.
• Emblematic plants [34,43,64]: rose, lilac, elderberry, apple, linden, oak, and spruce or fir planted as a Christmas tree.
• The most frequently recurring species of plants;
• Plant types: deciduous trees, conifers, deciduous shrubs, coniferous shrubs, climbers, perennials, plants in containers, and turf. In this place we also noted if there were no plants at all;
• “Advanced” forms of garden composition: sheared forms, grafted forms, rhythmic plantings, row plantings, perennial–seasonal flower beds, decorative stones, and sculptures.

The inventory was made based on Google Street View pictures, assuming that it pretended to be the views of the streetscape perceived by pedestrians. This method allows recognizing the nature of planting and species of plants visible from the street and has been used on numerous occasions [65,66,67] to study public space through eyes of users. To substantiate and verify the results, a site visit was carried out in each housing estate and the development of each plot was additionally assessed using oblique photographs in the Warszawa Ukośna application (https://ukosne.um.warszawa.pl/, accessed on 1 August 2022). The plant inventory took into account the size, colour, texture and availability of nursery stock at the time the estate was built. Plants and objects obscured by fences and not visible from the street were not inventoried.

2.3.2. Identification of Designers’ Preferences—A Survey

The questionnaire for designers aimed to find out to what extent they were prepared to use design tools to provide ecosystem services through a publicised part of the house garden (front garden). A study was carried out on n = 47 designers, professional home garden designers associated with the Polish Landscape Architecture Association (SAK). We asked them about acceptable front garden attributes relating to ES (

Table 2. Designers questionnaire—groups and their descriptions.

Group	Subgroup	Description
Regulating (Regulation and Maintenance ES)	Bird feeder	Bird feeders and houses
	Insect house	Pollinator’s hotels and feeders
	Drainage ditch	Irrigation and/or drainage ditches and channels
Provisioning	Small greenhouse	Glasshouses and frames for growing fruit and vegetables
	Composter	Compost bins
	Rainwater barrel	Rainwater containers
Cultural	Boulders	Pebbles, boulders, cobbles
	Sculptures	Sculptures and decors of secular nature
	Chapel	Small chapel, cross or figure in the garden or in house wall
	Figures of animals, gnomes	Symbolic figures of gnomes, fairy-tale characters and animals
	Reusing	Bottles, tires, containers as decors or utility items
	Sentimental, rustic decors	Old farm tools, a ladder wagon, ladder wagon wheel, etc.

). The ES attributes used in the literature are known by designers, so we decided to ask “not explicitly”, using designed forms rather than typical ES descriptions.

The survey was conducted using an anonymous form with the following questions:

• If according to the respondent the following items can be accepted in front gardens: bird feeder, pollinator house, composter, rainwater barrel, small greenhouse, drainage ditch, erratic boulder, sculpture, shrine, figurines of animals or dwarfs, used items repeatedly (bottles, tires, containers), items evoking sentiment, memories—souvenirs (old plough, ladder waggon, or waggon wheel). Answers had to be given on a Likert scale (−2 not at all, −1 rather not, 0—I have no opinion, 1—rather yes, 2—of course, yes!) [68].
• In addition, a question about age, gender, education and professional experience was asked.

2.4. Methods of Data Analysis

To illustrate the openness of front gardens, their transparency and inclusiveness, creating streetscape and landscape core [research question 1], we calculated the percentage share of plots with a given characteristic in the total plots researched. We did the same calculations in order to study characteristic features and ecosystem services chosen and preferred by the owners [research question 2]. The results were visualised using Microsoft Excel (version 16.56) diagrams.

As statistical analyses of the designers’ preferences [research question 3], we calculated the percentage share of respective characteristics for each rating scale in the total of questionnaires. We also calculated the median values (50th percentiles), 25th percentiles and 75th percentiles. A Kruskal–Wallis test was used in order to check if significant differences between the medians of the characteristics exist. Statistical analyses were carried out using PAST v. 4.03 [69].

We conducted a hierarchical cluster analysis (using PAST v. 4.03 [69] as well) in order to check for distinctive groups of VFG [research question 4]. The cluster analyses was carried out on the base of the first step results (identification of VFG attributes delivering ES—gardens’ features (see Section 2.3.1)). The VFG were grouped using Euclidian distance as distance measure and agglomeration according to Ward. The strength of the resulting nodes was tested by bootstrapping analysis (499 resamplings). Bootstrap proportions (percentage of replicates where the node is still supported) of ≥70% correspond to a probability of ≥95% that the respective clade is correct [70]. To better understand differences in VFG image, the major characteristics were described for the identified clusters. Characteristics present in at least 30% or 50% of the gardens belonging to the respective clusters were used to define dominant (30%) or very dominant (50%) features which characterise the different types distinguished by cluster analysis.

3. Results

3.1. VFG as a Part of Streetscape—Inclusiveness of VFG

A vast majority of the plots were fenced (Table S1). Only 2.5% had no physical fence, and observation allowed the claim that these were unoccupied properties. Although the garden’s interior was only moderately visible in up to 66% of the VFGs surveyed, in most cases, the fence allowed visual penetration of the front garden. Trees and higher (than the fence) shrubs or even their tops were clearly visible above fences and were inventoried. Sometimes, they were additionally provided with a hedge (22%) or climber (7.5%) to screen the interior view further.

Even in the case of a solid fence, garden owners arranged the space “in front” of their fence with an additional row of colourful shrubs or flowerbeds. We called it the pre-front garden. As many as 40% of the gardens used this option (Figure 5a).

3.2. Ecosystem Services in VFG

3.2.1. Attributes of ES in VFG—Owners’ Preferences

Exploring the ES attributes present in the VFG (means preferred by owners), we found that the primary medium for ES evidence are different types of plants. A service that is described as “Regulating. Trees” was observed in 93% of the VFGs. The remaining 7% were VFGs at uninhabited plots (in all inhabited properties, the gardens provided this service). We were able to correlate this attribute with the “Cultural” services presented by the attribute “Plants”, which we observed in 94% of the VFGs, and with green “Views” (from windows) (94%). Another quantitatively advanced attribute representing “Regulating” ES was “Bees” (37%), also observed due to plants attracting them. Other attributes in the “Regulating” ES were rarely observed: “Surfaces” (7.5%) and “Meadows” (1.6%) represented by flowering meadows and natural biodiverse turfs. Among the “Cultural” ES, there is also the attribute “Symbols”, which was recorded in 45% of plots. In the group of “Provisioning” ES the “Reservoirs” (34%) dominated (Figure 5b).

Regarding “Plants” coniferous (76%) and deciduous shrubs (62%) are the most common plants chosen by owners in VFGs. The next most abundant attribute is “Grasses” (50%), then we can enumerate coniferous (39%) and deciduous trees (35%). Seasonal plants in pots, perennials and climbers are in the range of 30–40% (Figure 5c).

Looking for “Emblematic” plants, “Christmas trees” (spruces and firs) and rose and lilac were found in larger quantities (31%, 13% and 14%, respectively) (Figure 5d). Considering the most common plants, there were a number of recurring genera and species: thuja (Thuja sp.)—occurring in 61% of VFG., Junipers (Juniperus sp.), barberries (Berberis sp.), and boxwoods (Buxus sempervirens)—only over 20%. There were also common to find “Conica” spruce (Picea glauca ‘Conica’), “Pissardii” plum (Prunus cerasifera “Pissardii”), Japanese spiraea (Spiraea japonica) in their different varieties; lavender (Lavandula angustifolia), ivy (Hedera helix), Virginia creeper (Parhenocissus quinquefolia, P. vitacea, P. tricuspidata), maple (Acer sp.), birch (Betula verrucosa, B. papyrifera), yew (Taxus baccata), pine (Pinus sp.) in different varieties and rhododendron (Rhododendron sp.) (Figure 5e).

Purposeful compositional progression was found less frequently in the VFG. The most common was to enclose plants in a delineated flowerbed (35%). Another observed compositional treatment was the row arrangement of plants. It was repeated in 24% of VFG, and in this group, rhythmic repetitions were observed in 10% of the plots. Next, regularity was observed in grafted forms (18%). Non-plant ornamental forms appeared sporadically—stones in nine gardens (2.33%), sculptures in six gardens (1.6%) (Figure 5f).

3.2.2. Ecosystem Services in VFG—Designers’ Preferences

Among the regulating ES, “bird feeders” received the highest ratings (23% and 49% positive—“yes”, “of course yes” answers) (Table S2). Designers’ preferences for “insect houses” were similarly distributed (30% and 34%). In contrast, “drainage ditch” are less acceptable than others among the regulating ES (28% and 17%).

Another group of ES, provisioning, compiled in percentages of ratings shows that designers completely disapprove of utilitarian elements such as a “composter” or a “small greenhouse” in a VFG (15% and 6%, and 21% and 17%, respectively). The only acceptable ones from provisioning ES are “rainwater barrel” (30%, 28%).

Further, if we follow the cultural ES we can claim that the designers rather unanimously consider the “boulders” in the front garden to be the correct form (40%, 32%); the highest score was given to “sculpture” (28%, 53%). The others have not been recognised by designers (values above 0, but only to a low degree): “figures”(15%, 13%), “reusing”materials (13%, 9%) and “sentimental rustic decors” (

Table 3. Summary of VFG attributes evaluated by designers: Percentage shares (%) of each rating scale for each attribute (bold—highest percentage share, italic—lowest percentage share), 75th percentiles, medians and 25th percentiles.

Ecosystem Services	Regulating			Provisioning			Cultural
rating scale/ percentile	bird feeder	insect house	drainage ditch	small greenhouse	composter	rainwater barrel	boulders	sculpture	shrine	figures	reusing	sentimental rustic decors
2	49	34	17	11	6	28	32	53	23	13	9	23
1	23	30	28	21	15	30	40	28	19	15	13	17
0	4	11	19	11	2	19	19	11	32	11	19	38
−1	13	15	21	30	13	13	4	2	0	11	19	2
−2	11	11	15	28	64	11	4	6	26	51	40	19
75th percentile	2	2	1	1	−1	2	2	2	1	1	0	1
Median	1	1	0	−1	−2	1	1	2	0	−2	−1	0
25th percentile	0	−1	−1	−2	−2	0	0	1	−2	−2	−2	0

).

The percentage shares of ratings were affirmed by median values, 75th percentiles and 25th percentiles (Table 3). The Kruskal–Wallis test revealed statistically significant differences between the medians of the characteristics (p < 0.001).

3.3. Groups of VFG Distinguished Based on Their Features

The hierarchical cluster analysis resulted in three main clusters. The first cluster, to which belong 127 VFG, is characterised by a very high percentage of gardens with “openwork fences” and “good view” (Figure 6). Bootstrapping confirmed a very strong separation of this cluster from the second and the third cluster (bootstrap proportion = 100), but the strength of the node regarding the latter ones is very weak (bootstrap proportion = 0). The second cluster consists of 92 VFG. It is more diversified at the composition–advancement level. With respect to composition, it is similar to the third cluster. The second cluster is distinguished by a high percentage of VFG with water reservoirs (provisioning service) and symbols (cultural service) and also a greater share of deciduous trees and shrubs. Regarding the composition-opening category, VFG with “in front”, “full fenced” and “moderately visible” have a high percentage share. VFG at the Composition–advancement level have more often than the other clusters “rhythms”, “grafted”, “flowerbeds” and also slightly more “symbols” (Figure 6). The third cluster consists of 166 VFG. As the second cluster, it is characterised by a very high percentage share of VFG with “full fenced” and “moderately visible” in the composition-opening category (Figure 6). The characteristics of VFGs presented collect the features that build their image. The dominant and very dominant characteristics of the involved gardens define the inclusivity and composition of the VFG in the three clusters as “Open”, “Closed but friendly” and “Closed”, respectively (

Table 4. Characteristics of vernacular front gardens belonging to the identified clusters based on their features (bold—>50%, italic—>30%).

Cluster/Type Name	Group of Features	Dominant/Very Dominant Features >30%; >50%	Ecosystem Services Group	Dominant/Very Dominant Features >30%; >50%
1 Open VFG	Composition—opening	openwork fence, good view	Regulating	trees, bees
	Composition—advancement	flowerbeds
			Provisioning	-
	Plants (type of)	deciduous shrubs, coniferous shrubs, grasses, creepers, perennials, potted plants,
	Most common plants (species)	Thuja occidentalis
			Cultural	plants, views, symbols (symbolic objects)
	Symbols (symbolic plants)	-
2 Closed, but friendly VFG	Composition—opening	(row of colourful shrubs or flowerbeds) in front, full-fenced, moderately visible, front hedge,	Regulating	trees, bees
	Composition—advancement	flowerbeds, rhythms, grafted, rows
			Provisioning	(water) reservoirs
	Plants (type of)	deciduous trees, coniferous trees, deciduous shrubs, coniferous shrubs, perennials, potted plants, grasses
	Most common plants (species)	Thuja occidentalis,Juniperus sp., Berberis sp., Buxus sempervirens
			Cultural	plants, views, symbols (symbolic objects)
	Symbols (symbolic plants)	Picea sp.
3 Closed VFG	Composition—opening	Full-fenced, moderately visible, (row of colourful shrubs or flowerbeds) in front	Regulating	trees
	Composition—advancement	-
			Provisioning	-
	Plants (type of)	deciduous shrubs, coniferous shrubs, deciduous trees, coniferous trees, potted plants, grasses
	Most common plants (species)	Thuja occidentalis
			Cultural	Plants, views, symbols (symbolic objects)
	Symbols (symbolic plants)	Picea sp.

).

Regarding spatial distribution of VFGs of the clusters, it is noteworthy that the individual settlements are characterised by the presence of gardens belonging to the same clusters with respect to most of the gardens surveyed in them. As far as the distribution in Warsaw is concerned, settlements located close to each other are characterised by similar proportions regarding the assignment of the gardens to clusters (Figure 7).

4. Discussion

4.1. Inclusiveness of VFG

Our results indicated that VFG create the streetscape of single-family residential sites in Warsaw. Although most of the investigated plots have a full, only partially transparent fence, based on those findings, thanks to the choices of garden owners, we can say that it is possible to describe attributes of such a streetscape. The presence of pre-front gardens and characteristic plants makes VFG shape the identity and variety of the site. Building a pre-front garden while obstructing the view of the interior garden demonstrates a high degree of understanding of the inclusive nature of VFG.

Many sources indicate lacking green public spaces in single-family housing areas [71,72,73]. Due to recurring plants, VFG can be considered a characteristic streetscape and can be treated as green public space, especially in places where it is missing. The fact that based on all the characteristics, groups of VFG regarding residential areas could be detected can be explained by two main findings. Firstly, our study draws attention to the visual accessibility of the VFG from the street. Transparency of the enclosure determines the development of the VFG. Where it is open, the development appears richer and the composition more complex. Secondly, gardens within each estate are clustered by similar development, which may indicate a desire to fit in with the community, thus expressed by the garden owners. The linear nature of the landscape core has already been indicated by Peter Goodchild [22], who has studied the landscape context in garden heritage conservation and protection. Other authors note that gardens form clusters along streets if they are visible from houses located along with them [74,75]. However, more and more single-family housing estates are being closed and excluded, becoming white spots on the map of public spaces [76,77]. They are also poorly connected due to the fact of being built directly on de-owned land, making them uncomfortable areas to walk [73].

4.2. VFG Attributes Providing ES

The dominant plants are shrubs, both deciduous and coniferous, and the most prominent species in their range are barberry, thujas, and junipers. Only in second place are beds of perennials and seasonal plants, mentioned in the literature as obvious [7,78]. It should also be noted that barberries have colourful foliage, making them a more durable and easier to maintain substitute for a colourful bed.

The basic aim of our study was to find out if VFG plays a role in the delivery of ecosystem services. Garden owners preferred “trees and shrubs improving air quality” (“Regulating”), “green/blue” view (“Cultural”) and ornamental plants and animals (“Provisioning”). In front gardens, these ornamental plant and animal functions are not produced, but only give pleasure to owners’ and pedestrians’ eyes. We can say that it is still a cultural service. In that case, cultural ES constitute the great majority.

However, decorative plants are common in VFG, the assumption about particular emblematic plants used in Polish gardens [35,65] and advanced composition is not confirmed. At the same time, we observed “new emblematic” plants, repeated in several plots, constituting more than 30% of them. There was a “Christmas tree”, plants in containers and delineated flowerbeds. Looking for emblems, i.e., plants recognizable as remarkable for Polish home gardens, we searched for spruces and firs as “Christmas trees” in front gardens, because we know from our design experience this form is desired in VFG by owners. We identified apple, lime, rose, lilac, oak, and elderberry as significant plant emblematic forms. However, our study showed that the plants we considered emblematic are not such at all. A new emblem turned out to be thuyas occurring in 61% of VFG junipers, barberries and boxwoods (over 20%).

Interestingly, 13% of the VFG are equipped with a “Kitchen garden” (Provisioning ES), a number similar to “Spaces for relaxation and playing in gardens”, which allows us to claim some similarity (Provisioning ES). The questions arise whether it is legitimate to say that the VFG are perhaps beginning to take over some of the functions of the main gardens or whether maybe some users do not mind combining the representative function with the practical one (the kitchen garden). As a partial result of the studies, this claim requires a deeper analysis and checking the correlation between the utilitarian and representative functions and ecosystem services. It may also be interesting to track further the impact of the SARS Cov-2 pandemic on designer preferences. Although they do not declare a significant change in design style (less than 25% of answers from 3 to 5), they are more willing to talk about the importance of natural values (32% of answers from 3 to 5), and much more willing (41% of answers from 3 to 5) about a place for recreation. It can be seen that the garden is no longer only decorative. In the literature, front gardens are considered representational spaces [79,80,81], while our findings have shown that they are also recreational spaces, as well as places for growing useful plants, and not only melliferous, but also the edible ones.

4.3. ES Preferred According to the Garden Designers

According to the designers—garden designers, the preferred ES are also “Cultural”, and “Regulating” ES represented by sculptures and bird feeders. Bearing in mind that they selected attributes from the list, we can confirm the similarity of results. However, while designers prefer more mature aesthetic attributes, they are not ready either to change the function of front garden to either production or nature. In addition to negating the notorious symbolic figures (gnomes, animal figurines), they cannot imagine either a composter or objects associated with recycling (tires, bottles). However, they do appear in the trendsetters’ show gardens [82].

In the case of the survey of designers, it seems reasonable to conclude that regarding cultural ES, a clear division between acceptance and denial of certain forms depicting culture is shown. The accepted ones include erratic boulders and sculptures. The negated ones include reusing elements and folk art crafts.

The designers’ opinions of the use of religious and sentimental elements are indifferent, so it appears that these aspects are rather left to the decision of the garden owner and not the designers. The result that designers’ opinions correlate with the ones gained for the studied gardens is visible especially in cultural and provisioning ES. The front garden is believed to have an established cultural role, as evidenced by choice of owners and designers, and delivering provisioning services is ensured by the presence of plants and animals. Based on semi-structured interviews with 44 gardeners in Barcelona, similar results were obtained [62]. In this study, most ecosystem services identified by the gardeners belonged to the cultural ones, and only one supporting ecosystem service was identified.

4.4. Groups of VFG. Differences and Similarities between Attributes of VFG and Designers Preferences concerning ES

The hierarchical cluster analysis showed that a major role in separating the VFG played compositional characteristics. First, the observation we described in Section 4.1 is confirmed. The main aspects differentiating the VFG are “Composition, opening”. Less important but noticeable is the difference resulting from the presence of flowerbeds which, although mentioned in the literature [53,54,55] are now found in only one third of the gardens, apparently distinguishing them from the others. The compositional attributes are given importance by the differentiating features of the ecosystem services—cultural ES. “Symbols” (Emblematics) are popular in the VFG—corresponding to “sculptures” and boulders as the positively assessed “cultural” ES by designers. The spatial distribution of the clusters studied indicates that gardens in individual settlements are similar. Some authors argue that by creating a shared estate landscape through similar front garden development, owners inform on their community to the outside; “neighbourhood norms influence gardening practices” [34,83,84].

Ecosystem services represented by attributes preferred by garden owners as detected based on the studied VFG was only partly confirmed by the opinion of the designers. The attitudes of owners and designers coincide when it comes to cultural ES. This confirms the traditional image of VFG as heritage. There is a difference regarding “Regulating”, which is not relevant to garden owners and at the same time is important to designers. The similarity concerns one element only: “Bees” (regulating ES) are significant to both garden owners and designers.

5. Conclusions

The results of our research confirmed that VFG plays a role in providing ecosystem services while being visually accessible and creating the streetscape. Both garden owners and designers choose those garden attributes related to delivering cultural and provisioning services. These attributes are mainly plants and visual access. Repeated groups of attributes, confirmed by clusters, demonstrate the uniqueness of these streetscapes. Therefore, residential sites with VFG can be treated in the category of green streets or living streets (woonerfs approach). This is another argument against gated communities and a reason not to close streets in housing estates to pedestrians.

The adopted method of using Google Street View images had been already used several times in similar types of research [65,66,67] and provided with valuable data and results. However, based on our results, we conclude that it does not allow for a precise inventory of plants in the investigated gardens. Therefore, we recommend in future studies additional use of a pool of qualitative research in the social research group (e.g., IDI interviews) and detailed inventories at different stages of the growing season.

Our conclusions are of practical value since single-family housing estates are undervalued as accessible green areas and considered exclusive areas. Our findings can be used in city area planning, especially in districts where the local plan allocates land for single-family housing. It also can be used in studies on the management of green areas on the city’s outskirts. Designers should appreciate front gardens and take inspiration from the VFG for design tools that can provide ecosystem services. Private gardens, especially their front parts (VFGs), are visually accessible to passers-by. VFGs build public space on a par with street greenery, becoming a valuable green justice tool in neighbourhoods lacking publicly accessible green spaces. The use of elements providing provisioning and regulating services such as edible plants and pro-natural solutions (e.g., planting species providing food for birds and pollinating insects) can be a valuable model for designers to follow. Designers, being trendsetters, adopting these aspects can be “multipliers” of the ES and thus improve the quality of public spaces by acting in the private areas of their investors’ plots.