Optimising the Vase Life of Cut Hydrangeas: A Review of the Impact of Various Treatments

Abstract

The vase life of cut hydrangea (Hydrangea macrophylla) flowers is a critical quality parameter, influencing their marketability and consumer satisfaction. This review examines the influence of various treatments on prolonging the postharvest lifespan of cut hydrangea blooms. It discusses hydrangea in general and its after-harvest mechanism, the vase life of cut hydrangea inflorescence in two phases, and conditions such as different storage temperatures and storage terms and length. It also highlights postharvest factors affecting cut flowers longevity like interventions targeting water balance, carbohydrate degradation, and sensitiveness to ethylene. Specific treatments that positively extend the life span of cut hydrangeas, such as sucrose, biocides, essential oil compounds, and commercial preservative solutions, are also evaluated. These treatments successfully increased the vase life of cut flowers from 3.6 to 12.3 days. The most effective solution for significantly extending the vase life of cut hydrangea flowers (‘Magical Jewel’) by 12.3 days was the combination of 1% sucrose and 8-HQS (8-hydroxyquinoline sulphate). The focus is on hydrangeas’ physiological and biochemical responses to these treatments, particularly their effects on water absorption, microbial activity, and the senescence process. By synthesising recent advancements and identifying research gaps, this review aims to provide actionable steps for growers, florists, and researchers to optimise the vase life of cut hydrangeas and improve the sustainability of their postharvest handling.

1. Introduction

The genus Hydrangea (Hydrangeaceae family) comprises approximately 80 species of flowering plants and is indigenous to southern and eastern Asia, as well as North, Central, and South America. This type of plant is included in shrubs and lianas [1,2,3]. In many countries, hydrangeas (Hydrangea spp.) are common ornamental plants that are grown as cut flowers, gardens, and potted plants. Recently, there has been an increase in demand for cut hydrangea flowers [4,5]. H. macrophylla is the most popular and extensively cultivated among Hydrangea species, such as H. paniculata, H. serrata, and H. arborescens [3,6]. Hydrangea inflorescences are divided into two categories—hortensia and lace caps—determined by how their showy, sterile flowers and smaller, fertile flowers are arranged [6].

Cut flowers have a short lifespan. Senescence in flowers is characterised by impairments in water intake, depletion of stored carbohydrates, and increases in respiratory activity and ethylene production [7]. As cut flowers age, bacteria and other microbes colonise the stem and water, releasing harmful substances. These cause vascular blockages, reduce water uptake and cellular activity, increase ethylene production, and hasten senescence [8].

Flower senescence, as the terminal stage of organ development, acts as a primary contributor leading to postharvest decline in quality impacting both the aesthetic appeal and economic worth of cut flowers [9,10]. This senescence process is tightly controlled by both internal growth signals and external environmental factors. Upon detecting these causes, petal tissues undergo critical changes—including membrane breakdown, reduced efficiency of antioxidant enzymes, and increased activity of proteases and nucleases. These hallmark features of senescence ultimately lead to the irreversible breakdown of petal cells [10]. Senescence may occur naturally and is a tightly coordinated and genetically controlled mechanism that progresses through a predictable genetic and biochemical pathway. This process can be initiated through endogenous signals or triggered by external factors [11,12]. Flower senescence is a pivotal stage in the developmental lifecycle of flowers, emerging after tissue specialisation and petal maturation but prior to seed formation and development. This phase is defined by systematic changes at cellular, physiological, and molecular levels [13].

Although senescence is inherently destructive, it is highly regulated, following a specific sequence of events. This process is often closely linked with programmed cell death (PCD), as evidenced by the senescence of leaves and petals [11]. Throughout the developmental and senescence phases of petal mesophyll cells, dynamic shifts in cellular organization and adjustments in cell wall thickness are observed. Vacuolar-mediated autolysis represents a distinct form of PCD in plant development. This form of PCD is activated during petal senescence [14]. Senescence in cut flowers is also hastened by oxidative stress resulting from wounding and water stress occurring during the market chain, which is next reflected in the low quality and longevity of plant material. Free radicals hasten senescence in cells and organs by activating enzymes responsible for the degradation of membrane structure. Biotic and abiotic stresses can upset the balance between production and elimination of free radicals [15].

There are many studies regarding how to delay the senescence of cut flowers through various alternatives. The following review will mention numerous treatments that have been used to prolong the life of cut hydrangea flowers after harvest. However, several research gaps and areas for further investigation can be identified to deepen the understanding of this issue and improve the sustainability and effectiveness of postharvest handling practices. Some research gaps are genotype-specific responses, molecular mechanisms of vase life extension, sustainable and eco-friendly alternatives, environmental impact and long-term safety, advanced handling, storage, and transport, and integrated microbiome management. Thus, this paper aims to review the effects of different treatments on extending the vase life of cut hydrangeas and give some alternative ideas to research deeper, such as studying different cultivars for treatment variability; omics-based studies on senescence and water balance; plant-based, biodegradable treatments; studies on colour, shape, and freshness retention; green chemistry; eco-toxicology assessments; cold chain optimization; water quality studies; microbiome-targeted biocides; and vase solution management.

2. Vase Life of Cut Hydrangea Flowers

In ornamental plants, flowers are essential organs whose developmental stages directly influence their commercial value. The culmination of petal development coincides with flower senescence—an irreversible, genetically regulated process driven by PCD. Premature senescence in cut flowers frequently leads to severe quality decline and significant economic losses during post-harvest storage and transportation [16]. As petals age, their cells undergo structural changes tied to PCD, such as tonoplast rupture followed by swift cytoplasmic breakdown. Morphologically, this PCD is categorised as either vacuolar cell death or autolytic PCD. Key features observed during petal cell PCD include an autophagy-like mechanism, chromatin condensation, and nuclear fragmentation, all hallmark traits of this regulated cellular degradation process [17]. Regardless of the plant organ studied, various cytological, physiological, and molecular changes due to PCD drive cellular breakdown through phytohormone fluctuations and activation of genetic pathways [18].

Most cut flowers reach the end of their vase life due in part to wilting, which results from reduced water absorption, elevated transpiration rates, and a limited ability of flower tissues to retain moisture [19]. During petal wilting, the breakdown of membrane fatty acids occurs, a process likely driven by non-enzymatic oxidative mechanisms [20]. Physiological indicators in cut flowers, such as relative electrical conductivity (REC), malondialdehyde (MDA), superoxide anion radical (O₂⁻), hydrogen peroxide (H₂O₂), and free proline content, can be elevated. Additionally, the activities of protective enzymes like superoxide dismutase (SOD), peroxidase (POD), and ascorbic acid peroxidase (APX) can also be increased. This means that the longevity of cut flowers can be extended [21]. Furthermore, improving relative fresh weight and antioxidant activities, inhibiting bacterial blockage in stems, reducing ethylene production, and regulating the expression of ethylene biosynthesis genes can also contribute to a longer vase life for cut flowers [22].

The vase life of cut flowers is a crucial attribute that determines their overall quality and appearance [23,24] and affects their commercial value, as it directly impacts their freshness and marketability [25]. Lifespan is also influenced by the balance between water absorption and evaporation [23]. For cut hydrangea flowers, which have grown in popularity as decorative elements for various events, the vase life is surely important. However, the longevity of these flowers in vases can vary significantly based on the management of postharvest solutions and treatments, which play a crucial role in maintaining the water balance and overall quality of the flowers [15].

Cut hydrangea flowers are available in two distinct forms: fresh-stage flowers, harvested just before or during flowering when the ornamental sepals are fully coloured, and antique-stage flowers, collected post-flowering when the decorative sepals change to green and/or red hues [4]. The harvest stage plays a crucial role in the vase life and quality of these flowers [6]. In fresh-stage cut hydrangea flowers, treatments such as defoliation, reduction of decorative florets, and covering of the inflorescence have been shown to effectively extend the vase life, likely through the suppression of transpiration [23]. Additionally, the regulation of vase life at this stage is influenced by transpiration from non-decorative floral organs [26]. Flowers harvested at the fresh stage exhibit different stomatal behaviours compared to those at the antique stage, leading to varying levels of water uptake and preservation of decorative sepals. In antique-stage cut hydrangea flowers, an increase in stomatal conductance in decorative sepals has been reported across multiple cultivars [6], indicating that reduced transpiration is not a major factor contributing to their prolonged vase life [4]. Additionally, the age of hydrangeas is a key factor in their physiology, directly influencing their ability to efficiently absorb and transport essential mineral elements. Recognising this relationship is vital for understanding and optimising nutrient uptake [27].

Kitamura et al. [4] reported that the harvesting stage, including both the fresh and antique phases, affected the vase life of cut hydrangea flowers. The vase life of fresh-stage cut flowers varied among cultivars, ranging from 7.0 to 28.5 days, while minimum vase life of antique-stage cut flowers was 9.0, and the maximum lifespan was 2.5 times longer (71.6 days) than of the fresh-stage cut flowers. In the correlation of the vase life between both stages, the vase life of the antique-stage flowers was significantly longer than that of fresh-stage flowers for some cultivars, such as ‘Endless Summer’ (13.2 days), ‘Glowing Alps’ (7.5 days), ‘Grünherz’ (9.8 days), ‘Masja’ (59.9 days), and ‘Temari Ezo’ (32.5 days). Aros et al. [28] claimed that in the fresh stage, treating with deionised water alone, or in combination with ClO₂, resulted in the longest vase life, lasting an average of 17.7 days. The deionised water produced the longest vase life of 32.7 days, significantly outperforming all other treatments at the antique stage.

Temperature significantly affects the vase life of cut hydrangea flowers by affecting hydration, respiration, transpiration, and overall floral quality. The temperature at which hydrangea flowers are stored and displayed has a direct impact on their longevity. Lee et al. [29] reveals that prolonged storage at unsuitable temperatures reduces vase life, causing changes in colour and hydration levels. Similarly, Kazaz et al. [30] found that maintaining a stable room temperature (around 21 °C) with controlled humidity improves the vase life by supporting consistent solution uptake and minimising water stress. Temperature affects transpiration rates, which are crucial for water loss in cut hydrangea flowers. Kitamura and Ueno [23] reported that controlling transpiration through temperature regulation can effectively extend vase life. Additionally, using preservative solutions at specific temperatures prevent the negative effects of higher temperatures [25]. Non-decorative floral organs also impact transpiration rates. Kitamura et al. [6] discovered that removing these organs, along with optimising temperature, reduces water loss and extends vase life. Consistently maintaining room temperatures around 22 °C with moderate humidity is linked to longer vase life. This finding is corroborated by research on various postharvest treatments (tap water, 1% Chrysal Professional III, 2% sucrose + 250 mg L⁻¹ 8-hydroxquinoline + 100 mg L⁻¹ citric acid) on cut H. macrophylla ‘Verena’ tested at room temperature [25].

Storage conditions, including temperature and duration, significantly impact flower quality. Short-term storage is preferable to maintain aesthetic and structural integrity [29]. Cut hydrangea flowers had a vase life of 7–9 days after 20 days of storage. However, stems stored for 35 days exhibited a reduced vase life of only 2 days. No significant difference in vase life was observed between precooled and non-precooled stems. Botrytis infection occurred in only one of the treatments without fungicide, with a 12.5% incidence rate, so the fungicide’s effectiveness was not assessed by Schiappacasse et al. [31].

3. Postharvest Factors Influencing the Vase Life of Cut Flowers

3.1. Water Balance

Vase life, a key indicator of cut flower quality, is significantly influenced by the balance between water absorption and evaporation [23], as the flower bud opening does not include cell mitotic divisions in petals but depends on a free water influx and an increase in the volume of the existing cells [32]. Each disturbance of water relations prevents proper flower opening and constitutes a water stress which hastens flower senescence. Flower stems stop absorbing and conducting water when their vessels get blocked [32]. Microbial growth, air embolisms, or physical blockages in the stem can restrict water uptake. These blockages often form when flowers are not immediately placed in water after cutting or when water contains impurities [33]. Cut hydrangeas experience a shortened vase life primarily due to blockages in their vascular system (occlusions), resulting from air embolisms and microbial activity. This diminished absorption leads to rapid wilting and browning of the petals [6].

Transpiration through stomata is a major pathway of water loss in cut flowers. Environmental factors such as high temperatures, low humidity, and strong air currents increase transpiration rates, disrupting water balance and leading to dehydration [6]. Reducing transpiration through environmental control or defoliation has been shown to enhance vase life [23]. Hydrangeas have large decorative sepals with high water loss rates [6]. Cooler temperatures and higher humidity reduce transpiration rates, preserving water balance. Storage and display conditions significantly impact flower longevity [23,29]. When water loss exceeds uptake, flowers lose turgor pressure, leading to wilting, discoloration, and accelerated ageing. This imbalance also impairs the transport of nutrients and floral preservatives added to vase solutions, further reducing flower quality [29].

There are some strategies to enhance plant water balance, such as chemical treatments, environmental controls, and stem treatments. Solutions containing biocides like 8-HQS prevent microbial growth, while citric acid enhances water uptake [34]. Recutting stems underwater prevents air embolisms, promoting continuous water uptake [28].

Water shortage is the primary factor influencing the postharvest longevity of cut H. macrophylla, with transpiration playing the central role in maintaining water balance. Variations in stomatal density and the rate at which stomata open are the main reasons for differences in vase life among various cultivars of cut H. macrophylla [35]. In addition, Ahmad et al. [36] reported the impact of water quality on the postharvest longevity and condition of cut H. macrophylla flowers. A lower solution pH (2.9–3.3), higher electrical conductivity (up to 2.5 dS m⁻¹), and the application of floral preservatives were found to extend the vase life of hydrangeas from 7.3 to 15.4 days.

The role of microbial communities in vase solutions and their interactions with stem tissues remains largely unexplored but could be critical for improving water uptake and preventing blockages. Future research should focus on microbiome-targeted strategies, such as beneficial microorganisms or precision biocides.

3.2. Carbohydrates Deterioration

The vase life of cut flowers is intricately connected to their carbohydrate levels, which are crucial for energy supply, flower opening, and delaying senescence. Carbohydrates, as the primary source of energy, play a critical role in maintaining flower quality. The elevated carbohydrate levels were influenced by repositioning the leaves and altering the direction of light exposure [37]. Higher carbohydrate levels correlate with extended vase life, especially when environmental conditions like light and temperature optimise carbohydrate retention. Soluble carbohydrates delay senescence by providing the necessary energy for flower opening. Halevy and Mayak [38] emphasised the role of carbohydrates in maintaining respiration rates. The gradual decline in carbohydrates due to insufficient photosynthesis or uptake during postharvest periods accelerates senescence [24]. Sugar starvation is linked to lipid degradation and loss of cellular integrity in petals [39]. Reduced carbohydrate availability to flowers results in a higher rate of flower abscission [40].

There is a correlation between carbohydrate deterioration and cut flower senescence [41]. Carbohydrate depletion is known to lead to metabolic failure and a reduced vase life in cut flowers. Interventions such as sucrose supplementation, improved storage conditions, and sugar-based preservatives have been shown to mitigate senescence by providing necessary substrates for respiration and delaying ethylene biosynthesis or sensitivity. A higher carbohydrate content postpones senescence, thus extending vase life [42]. Elevated light levels enhanced the dry matter percentage and concentrations of ascorbic acid (AsA) and carbohydrates at harvest, and these heightened levels were retained throughout the post-harvest period. Higher light exposure additionally prolonged the shelf life. A positive correlation was observed between the initial AsA and carbohydrate concentrations and the shelf-life duration, suggesting that the extended shelf life depends on enhanced energy reserves and antioxidant levels present at harvest [43].

Sucrose delays senescence by reducing osmotic stress and stabilising hormone levels, which demonstrates that an external carbohydrate supply can compensate for internal deterioration. Sugar-containing preservatives maintain carbohydrate pools and delay senescence in clematis flowers, ensuring better postharvest quality [15]. A study by Zhang et al. [44] revealed that glucose application induces anthocyanin accumulation in cut Paeonia suffruticosa flowers. Anthocyanins, key pigments responsible for diverse colorations ranging from pink to purple in plants—particularly in flowers—play a critical role in maintaining vibrant hues. Sustaining or enhancing anthocyanin levels is essential for delaying or preventing colour fading in flowers, thereby preserving their ornamental appeal. Moreover, a 500 mM sucrose-holding solution effectively delayed the decline in anthocyanin content and preserved the ornamental quality of cut flowers for up to 38 days postharvest [45]. Additionally, sucrose supplementation enhanced flower diameter, soluble sugar levels, and total antioxidant capacity while reducing malondialdehyde content, which is associated with oxidative stress.

Carbohydrate dynamics vary across flower species and cultivars. The flowering induction in Hydrangea macrophylla ‘Endless Summer’ is orchestrated by an intricate genetic network integrating multiple signalling pathways, which collectively sustain continuous blooming during the growing season. This process involves the coordinated activity of genes associated with sugar metabolism, hormonal regulation, and flowering mechanisms, highlighting their critical role in the plant’s ability to initiate and maintain repeated flowering cycles [46]. Total sugars—primarily comprising sugars, sugar alcohols, and sugar intermediates—initially rise and subsequently decline during floral development in Lycoris radiata [47]. These results align with prior research documenting similar sugar depletion across developmental stages in various plant species. For instance, in Lilium pumilum, total sugars (reducing and non-reducing sugars) and starch content decreased during floral maturation, while soluble sugars and starch declined in Gentiana macrophylla, coinciding with a gradual increase in celluloses, hemicelluloses, and lignin across four developmental stages [48]. Similarly, in Narcissus tazetta, total sugars, including reducing and non-reducing sugars, showed an initial accumulation, followed by a reduction, as flowers progressed through development and senescence [49].

Reducing sugars dominate mature petals’ sugar pool. Starch is vital in woody plants, including hydrangeas. Flower respiration peaks at bloom, declines with age, briefly spikes during wilting, then drops—mirroring climacteric fruit respiration. As carbohydrates influence vase life, adding sugars to vase solutions post-harvest enhances longevity. Preventing carbohydrate depletion is essential for prolonging vase life. Lisianthus flowers treated with carbohydrate solutions exhibited improved the vase life [50].

3.3. Ethylene Sensitivity

Ethylene, a gaseous plant hormone, acts as a critical regulator within the complex network of plant developmental processes, governing stages from germination to senescence under both optimal and stressful environmental conditions. This hormone is ubiquitously detected across various plant tissues, such as leaves and flowers [51]. The primary determinants of vase life duration are closely linked to a flower’s sensitivity to ethylene. In ethylene-sensitive cultivars, the vase life was directly correlated with specific transcript levels triggered by ethylene exposure [52].

The vase life of hydrangeas, like other cut flowers, is influenced by various physiochemical processes and is reduced by the production of ethylene. Freshly harvested hydrangeas are sensitive to ethylene, whereas flowers harvested at the mature, classic stage are not affected by ethylene [31]. Ethylene, a phytohormone, has been shown to trigger defoliation and enhance flower development in two H. macrophylla cultivars (Hm080108 and Hm080109). It has potential applications in hydrangea cultivation, serving as a defoliant and flowering inducer. Ethylene treatments aimed at boosting flowering could improve plant quality; however, treatment protocols require optimisation, and variations between cultivars must be carefully considered. Despite its benefits during production, ethylene negatively impacts hydrangea plants during the postharvest phase, potentially diminishing their quality [53].

The biosynthesis of ethylene in plants is metabolically regulated during both developmental growth and senescence. In the case of cut Mokara orchid flowers, variations in their vase life are linked to their distinct ethylene production rates, which control key developmental stages, such as bud opening and floret senescence. Ethylene plays a pivotal role in regulating flower senescence in Mokara, with pretreatment using ethylene inhibitors markedly extending vase life. This indicates that ethylene, rather than water-related factors, is the primary determinant of longevity differences in these hybrids [54]. Controlling ethylene during the pre-harvest stage also contributes to an extended vase life. Studies on roses suggest that regulating ethylene levels before harvest enhances energy metabolism and antioxidant activity, which subsequently improves postharvest longevity [55]. Flowers sensitive to ethylene, such as carnations, experience reduced vase life due to ethylene-induced senescence. As another example, ethylene exposure in cut roses reduces water uptake, accelerates wilting, and diminishes vase life, while ethylene-insensitive cultivars maintain their freshness for longer durations [56]. One prominent method of reducing the ethylene damages involves using 1-Methylcyclopropene (1-MCP), an ethylene action inhibitor that extends the vase life of ethylene-sensitive flowers, such as carnation by blocking ethylene receptors [57]. Similarly, silver nanoparticles have proven effective in carnations, where they reduce ethylene sensitivity and prolong vase life [58].

4. Effect of Treatments on the Vase Life of Cut Hydrangea Flowers

4.1. Effect of Sugars on Vase Life of Cut Hydrangea Flowers

Exogenous sucrose or glucose treatments extend vase life by maintaining cell turgor, membrane integrity, and water balance. Sugars act as osmotic agents and energy substrates, counteracting carbohydrate depletion postharvest [39]. Sugar is also involved in delaying petal senescence by suppressing ethylene synthesis [59]. Glucose exhibited distinct daily solution uptake dynamics compared to other sugars. When mannitol was absent, glucose effectively enhanced both daily and total solution absorption in cut hydrangea flowers. Even when combined with otherwise ineffective mannitol or other sugars, glucose further increased the daily uptake. This elevated absorption may be attributed to reduced xylem blockage. Moreover, glucose slowed the decline in relative fresh weight, while mannitol accelerated it, indicating a clear correlation with extended vase life [42].

Sugars such as sucrose play important roles in keeping the quality of many cut flowers since there is a limited amount of sugar present in such flowers. Besides osmolytes, the role of sugars in extending the vase life is also influenced by respiratory substrates and synthetic compounds. Therefore, sugars are included in preservatives [60]. The usage of sucrose is beneficial for extending the vase life of cut hydrangea flowers [30]. The application of sucrose in pulsing solutions or as a component of vase solutions increases water balance and energy or delays senescence by reducing ethylene production [7]. Postharvest treatments, such as combining glucose with 8-HQS, have shown promise in enhancing water uptake and maintaining the turgidity of flowers [34].

Studies like Yang et al. [25] emphasise the importance of sucrose in postharvest treatments, showing that its inclusion in preservative solutions increases the vase life by mitigating fresh weight loss. Similarly, Kazaz et al. [5] demonstrated the benefits of combining bactericides with sucrose, leading to extended longevity and better water uptake. In addition, research by Kılıç et al. [60] highlighted the synergistic effects of sucrose with other preservatives, improving the quality and longevity of hydrangeas. This finding aligns with earlier observations that sucrose not only prevents senescence but also enhances the visual appeal of inflorescences. Finally, Amnuaykan [61] discussed the comparative benefits of different sugars and revealed that the vase solution containing 5% glucose had the longest vase life, lasting 12.4 days, compared to 8.9 days for the control solution with distilled water. This outcome was linked to factors such as total solution uptake, the time required to reach maximum inflorescence diameter, the highest sepal hardness score, chlorophyll content, and sepal electrolyte leakage. The results suggest that glucose alone may prolong the vase life of hydrangeas by suppressing the ethylene-signalling pathway. On the other hand, considering sepal size and colour, the 3% glucose treatment, which, according to Amnuaykan [61], achieved the second-longest vase life, appears to be the optimal concentration for enhancing both flower quality and longevity.

4.2. Effect of Biocides on Vase Life of Cut Hydrangea Flowers

A study specifically investigating H. macrophylla observed that the combination of biocides and sugars in preservative solutions significantly enhanced vase life, maintained petal turgor, and preserved biochemical integrity by minimising oxidative stress and microbial contamination [7]. Biocides such as nanosilver have shown efficacy in suppressing microbial growth and thereby delaying senescence markers, such as the reactive oxygen species (ROS) accumulation, membrane leakage, and chlorophyll degradation [62].

Cut hydrangea flowers are highly vulnerable to water stress, which leads to a negative water balance in the calyx under insufficient water conditions. This stress is primarily caused by disrupted water flow and vascular blockage at the stem’s end [3]. Like most cut flowers, hydrangeas initially absorb water rapidly, but uptake declines as microbial growth and air embolisms obstruct vascular systems [63]. Microbial growth in vase water or on the dipped portion of the stem causes vascular blockage of xylem vessels, increasing stem resistance to water flow and decreasing vase life [64]. Solutions containing biocides suppress bacterial growth and extend the longevity of the cut flowers [62]. Bika et al. [65] examined the effect of fungicides on the vase life of hydrangea flowers. Preventive preharvest whole-plant sprays and postharvest dips of fungicides like isofetamid and fluxapyroxad + pyraclostrobin significantly reduced postharvest botrytis blight severity and the area under the disease progress curve (AUDPC) compared to untreated, inoculated controls. Postharvest dips of fludioxonil and the biofungicide Aureobasidium pullulans (strains DSM 14940 and DSM 14941) were also highly effective in minimising disease severity and progression (AUDPC). These treatments extended the postharvest vase life of bigleaf hydrangea flowers, likely due to reduced botrytis blight severity, which helped to maintain proper physiological functions.

The vase life of cut hydrangea flowers has been positively extended through the application of 8-HQS [5,33], 8-HQS combined with sucrose, and organic acids [66]. The longest vase life of H. macrophylla ‘Ankong Rose’ was recorded with 8-HQS, lasting 12.1 days, and 3.6 days longer than that of control (distilled water). This was followed by flowers treated with 76 mg L⁻¹ of glycolic acid (GA), which had a vase life of 10.7 days, and those treated with 38 mg L⁻¹ of GA, lasting 9.7 days. In contrast, the shortest vase life was observed with citric acid 100 mg L⁻¹, which lasted only 7.2 days, being 15% shorter than that of the control [33]. The application of 200 mg L⁻¹ 8-HQS significantly prolonged the vase life of cut hydrangea flowers in H. macrophylla ‘Schneeball’ flowers, resulting in almost 16 days, compared to the treatment of GA and control. Even with the application of other concentrations of 8-HQS, 200 mg L⁻¹ 8-HQS treatment extended the vase life of hydrangea flowers [5]. Kazaz et al. [30] reported that both thymol and 8-HQS (200 mg L⁻¹) applications positively affected the longevity of cut hydrangea flowers when the sucrose was added.

In the case of the cultivar ‘Magical Brilliant’, cut flower life was extended 4.7 days longer than the distilled water in the 3% sucrose + 8-HQS combination. This was the longest vase life amongst other treatments, accounting for 9.3 days. The treatment of 8-HQS alone and mixed with 1% sucrose resulted in significant extended of cut flower lifespan, 7.7 and 9.0, respectively [66]. In the ‘Magical Jewel’ case, the application of 1% sucrose + 8-HQS treatment and 3% sucrose + 8-HQS treatment significantly prolonged the lifespan of cut flower by 12.3 and 12.0 days, compared to 7.7 days in distilled water [66].

Interestingly, the preservative solution’s acidity was considered an important factor in the vase life of cut flowers. The lifespan of cut flowers at the treatment of the 3% sucrose + 8-HQS combination at pH 3.5 was the longest, accounting for 9.0 days and 21.7 days for cultivar ‘Magical Brilliant’ and ‘Magical Jewel’, respectively. Such a combination treatment prolonged the longevity of ‘Magical Brilliant’ 98% and ‘Magical Jewel’ 156% compared to distilled water treatment [66].

The organic acids in the preservation solution significantly affects the longevity of cut hydrangeas. In the treatment of citric acid 100 mg per litre, both ‘Magical Brilliant’ and ‘Magical Jewel’ had the longest cut bloom lifespan at 12.3 and 22.7 days, respectively, extending the vase life 4–5 days, compared to distilled water [66]. Additionally, the treatment of cut hydrangea flowers with acidic electrolyzed water (HOCl 5 μL·L⁻¹, pH 5.0–6.5) in a vase after harvest prolonged their vase life [67]. Certain germicides are recommended to inhibit microbial overgrowth [63], while organic acids enhance water absorption by lowering water pH [68]. In cut hydrangeas, sucrose and 8-HQS treatments had the most significant effects on fresh weight and solution absorption [66].

4.3. Effect of Abcisic Acid (ABA) on Vase Life of Cut Hydrangea Flowers

ABA, a critical plant hormone, regulates water loss in plants by promoting stomatal closure during water stress conditions [19], uptake of water and ions, and leaf abscission and senescence that represent key physiological processes influencing plant development [69]. Exogenous ABA deactivates quickly due to light-induced isomerization and metabolism, limiting its use. In contrast, ABA analogues (chemically similar to natural ABA) with slight structural changes offer greater stability and uptake, enhancing their effectiveness [70].

The vase life of cut hydrangea flowers can also be affected by ABA. Metabolomic studies highlight that ABA levels are linked to physiological changes, such as senescence and water retention, in hybrid hydrangea flowers, underscoring its role in maintaining floral quality [71]. ABA-regulated processes, including vase life and flower senescence, have been explored in several cut flowers, including hydrangeas. The effects of ABA appear to vary, showing both beneficial and adverse outcomes depending on the application method [72]. ABA treatments have been associated with delaying drought-induced wilting while accelerating senescence and flower abscission in other ornamentals, effects that may also apply to hydrangeas [73].

Studies on xylem sap ABA concentrations suggest that ABA contributes to water regulation and stress responses in hydrangeas under cold conditions, which could indirectly impact the longevity of cut flowers. Applying ABA during cold acclimation influences carbohydrates and bark proteins, potentially enhancing the resilience of hydrangea cut flowers in cold environments [74]. ABA has been observed to influence the quality of antique-stage cut hydrangea flowers by enhancing stomatal conductance, which is essential for preserving decorative sepals. This indicates that ABA treatments may improve postharvest flower quality, as evidenced by the extended vase life of 12 to 18, which were significantly longer than the control blooms [6]. ABA has been shown to affect flower bud differentiation and development, which could have downstream implications for the postharvest performance of H. macrophylla and similar species [75]. Research on shelf life under varying ABA spray concentrations revealed that ABA treatments influence the quality and longevity of potted hydrangeas, potentially offering insights relevant to cut flowers as well [76].

4.4. Effect of Essential Oil Compounds on Vase Life of Cut Hydrangea Flowers

The environmental and health concerns associated with synthetic preservatives and chemical biocides highlight the need for natural, biodegradable alternatives such as essential oils. According to Crocoll [77], essential oils, as natural, safe, and environmentally sustainable substances, demonstrate potent antimicrobial activity against pathogens due to their monoterpenoid phenol content.

Some essential oil compounds such as thymol and carvacrol alone or mixed with sucrose can effectively extend the vase life of cut hydrangea flowers [30,60]. Kazaz et al. [30] reported that treatments with thymol at 100 mg L⁻¹, both with and without 1% sucrose, as well as thymol at 150 and 200 mg L⁻¹ with sucrose, significantly prolonged the vase life of cut hydrangea flowers. The vase life of cut hydrangeas treated with 150 mg L⁻¹ of thymol plus 1% sucrose was almost 6 days longer than that of the control.

Also, Kılıç et al. [60] highlighted that thymol 150 mg L⁻¹ with sucrose affected the longest lifespan of cut hydrangea flowers (12.1 days), which was 42% days longer than those in distilled water (control). Such a result was no significant difference from treatments of carvacrol 150 mg L⁻¹ + sucrose, thymol 100 mg L⁻¹ + sucrose, and thymol 50 and 100 mg L⁻¹, accounting for 12.0 days, 11.4 days, and 10.1 days.

Thymol and carvacrol, known for their antimicrobial properties [78], improve relative fresh weight by reducing xylem blockage and enhancing water uptake [60]. The maximum total solution uptake among the treatments during vase life and fresh weight of cut hydrangea flowers was obtained at the combination of thymol and sucrose [30,60].

Future studies should investigate plant-based extracts, essential oils, and microbial antagonists as safer options for controlling microbial growth and enhancing water uptake. Exploring green-chemistry-based preservatives could also help reduce the ecological impact of the floriculture industry.

4.5. Effect of Commercial Preservative Solutions on Vase Life of Cut Hydrangea Flowers

Treatments with Chrysal RVB and Floralife Quick Dip increased total water absorption, prolonged maintenance of water balance, and enhanced relative fresh weight in cut hydrangeas. These results underscore the vital role of pretreatment methods and preservative solutions, demonstrating that appropriate floral preservatives and pretreatment protocols can markedly improve the marketability and longevity of hydrangea cut flowers [25].

It is pivotal to use appropriate preservative solutions and pretreatments to improve the marketability and longevity of cut hydrangea flowers. Commercial preservative solutions like Chrysal Professional have been shown to effectively prolong the lifespan of cut hydrangeas. This is a universal product by Chrysal, which stimulates water uptake because of an antibacterial compound. Yang et al. [25] found that certain preservatives, such as Chrysal Professional and sucrose combined with 8-hydroxyquinoline and citric acid, significantly extended the vase life of hydrangeas. The vase life was extended by 3.4 days for Chrysal Professional and 1.4 days for the sucrose treatment, in comparison with tap water. Additionally, pretreatment solutions like Chrysal RVB and Floralife Quick Dip further extended vase life by 5.9 and 4.6 days. Chrysal RVB is recommended for woody cut flowers to prevent blockages of the vascular bundles and thus wilting. Floralife Quick Dip helps maximise solution uptake and provides flowers with a quick hydration boost. It is designed to reduce bent neck and droopy stems.

Moreover, the use of homemade preservative formulations as alternatives to commercial solutions showed that these alternatives often provide comparable benefits for the vase life extension of cut flowers, such as lisianthus, snapdragon, and zinnia. Regular use of these preservative solutions extended the vase’s life and postponed the senescence of all the tested flower species [79]. Therefore, such preservatives can be used in extending cut hydrangea flower lifespan.

5. Conclusions and Future Research Directions

Specific treatments like sugars, biocides, and essential oils are shown to enhance vase life by improving water absorption, reducing microbial growth, and delaying senescence. Such treatments effectively extended the vase life of cut flowers from 3.6 to 12.3 days. The most effective to significantly extend the vase life of cut hydrangea flowers (‘Magical Jewel’) to 12.3 days was 1% sucrose combined with 8-HQS. The analysis highlights recent advances, offers practical postharvest tips, and identifies research gaps to improve the sustainability and quality of cut hydrangeas.

Although treatments like sucrose combined with 8-HQS have shown promising results, the varying responses among different hydrangea cultivars remain poorly understood. Future research should prioritise evaluating the efficacy of vase life-extending treatments across a range of hydrangea genotypes. This will help create customised protocols that consider varietal differences in physiology, water balance, and ethylene sensitivity. In addition, floral preservatives are moving toward safer, eco-friendly alternatives to 8-HQS. Using biological preservatives (chitosan), a mix of nano silver, citric acid, and essential oils or plant extracts helps control microbes and keep flowers hydrated while being better for both the flowers and the environment. The molecular and biochemical mechanisms behind the positive effects of postharvest treatments on cut hydrangeas are still unclear. Advanced integrative approaches, such as transcriptomics, proteomics, and metabolomics, are needed to uncover the cellular and molecular processes regulating senescence, water uptake, and carbohydrate metabolism. Identifying biomarkers associated with vase life could offer predictive tools for breeders and florists.

Beyond chemical treatments, advancements in cold storage, packaging, and transport are essential for maintaining hydrangea quality. Research should focus on integrated handling systems, including smart packaging, modified atmosphere storage, and temperature management, to reduce stress and delay senescence during the supply chain.

Addressing these research directions will enable a comprehensive improvement in the vase life management of cut hydrangeas, combining scientific innovation, and environmental responsibility. Interdisciplinary collaboration among plant scientists, microbiologists, and floriculturists will be essential to advance this field and ensure that cut hydrangeas remain a sustainable and attractive product in the global floriculture market.