Redbud production.

The average total size of the nurseries was around 212 acres. As far as the types of redbud business operations, 65% of the growers were involved in container production, 44% were involved in ball and burlapped production, 29% were involved in bareroot production, and 9% were involved in liner production. Around 18% of respondents were involved other types of redbud production such as landscape companies/contractors, local government, horticulturists, etc. According to the growers’ responses of their production numbers the previous year, they produced 19,740 ball and burlapped plants worth $1,855,400, 14,390 container plants worth $1,068,000, 16,650 bareroot plants worth $59,000, 5,800 seedling liners (bareroot) worth $376,200, and 700 seedling liners (container) worth $10,000. Redbud producers respondent to the survey represented 12.6% of the total redbud production value in the United States. Additionally, the growers were asked to provide more information about the cultivars and species of redbud that they produce in their nurseries (Fig. 1). Eastern redbud was one of the most commonly produced redbuds, followed by some cultivars of redbud including Forest Pansy, Ruby Falls, Flame Thrower, Rising Sun, Appalachian, and Merlot. Cultivars that produced less than 5% include Black Pearl, Carolina Sweetheart, Royal White, Sparkling Wine, Burgundy Hearts, Rise and Shine, Heart of Gold, Little Woody, Oklahoma, and Bubble Gum. There are some other cultivars that growers like to produce such as Tennessee Pink, Golden Falls, Northern Herald, Pink Pom Poms, Garden Gems Amethyst, Alley Cat, Ace of Hearts, Traveller, Hearts A’fire, Kay’s Early Hope, Whitewater, Lavender Twist, Don Egolf, and Shirobana (Alba). Over the past decade, the popularity of redbud plants has shown significant growth, with increasing demand driven by their aesthetic appeal and versatility in landscaping. As a result, the market now offers a diverse range of more than 60 distinct cultivars, each with unique characteristics that cater to various preferences and environmental conditions. In this survey, respondents identified more than 30 cultivars that they produced in their nurseries, further highlighting the growing popularity of redbud cultivars within the nursery industry. Considering the fact that many nurseries producing redbuds are also cultivating a wide variety of other plants, their current involvement in producing multiple cultivars of redbud indicates the popularity it holds in the customer market.

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Plant health.

Over the past few growing seasons, 77% of growers in our sample have noticed VSD-related symptoms with redbud plants, and 23% did not notice symptoms. Survey respondents have been experiencing VSD issues for last 5 years, with 2022 showing the highest incidence at around 30% of responses. This was followed by 2021 at 28%, 2020 at 16%, and 2019 at 15%, according to the survey data. Although VSD was first observed in 2019 and confirmed in 2020 in Tennessee, 9% of respondents to this survey reported that they had observed VSD symptoms as early as 2018. This aligns with the existing literature, which documents the presence of VSD symptoms in North Carolina maple trees in 2018 (McClellan 2023). It is suggested that the VSD issue may have been present for several years, as identified by the survey respondents, even though it was not officially recorded until later.

According to the responses, VSD-related symptoms are most commonly observed in the summer (37%), followed by spring (32%), fall (20%), and winter (11%). This distribution of symptoms could be attributed to several factors, one of which may be related to the cultivars, as differences in symptom appearance have been previously reported to be associated with different cultivars (Liyanapathiranage et al. 2025). It was also found in the survey that respondents indicated leaves (25%) as the most affected plant part due to VSD, followed by stems (24%) and branches/twigs (25%). Respondents identified the most common VSD symptoms they have observed over the years, with wilting (16%), dieback on plant tip (14%), vascular streaking (12%), plant death (12%), yellowing (11%), and defoliation (10%) being the most frequently reported symptoms. VSD-related symptoms have been thoroughly described in a few recent publications, and the symptoms identified as major ones by the respondents have also been documented in these publications (Beckerman 2022; Bily et al. 2023; Liyanapathiranage et al. 2025; McClellan 2023). This suggests that the survey participants have substantial understanding of how to identify VSD symptomatic plants in their nurseries.

To understand the distribution of VSD symptoms in nurseries, the survey asked respondents to select the areas where they most observed VSD symptoms and whether the distribution was limited to general areas, scattered, or restricted to certain cultivars. According to the survey results, 32% of respondents observed a general distribution of symptoms, 27% reported a scattered distribution, and 16% believed the symptoms were linked to specific cultivars. Redbud plants in the life stages of ball and burlapped (29%), container (24%), bare root (17%), and budded liners (14%) were most commonly identified as exhibiting VSD symptoms. Respondents also identified the redbud production stages in which they observed the most VSD symptoms. According to the results, field (43%), container (28%), landscape (18%), and pot-in-pot (11%) were identified as the stages during which VSD symptoms were most observed. Many diagnostic laboratories across the country have confirmed VSD in redbud plants at different production stages as well as in natural settings, further supporting the observations indicated by the respondents (Beckerman 2022; Bily et al. 2023).

The survey questions were designed to assess respondents’ awareness of redbud cultivars’ susceptibility to VSD. Initially, participants were asked whether the VSD symptoms they observed were specific to certain redbud cultivars, and 75% did not believe the symptoms were cultivar specific. Among the respondents who mentioned that VSD symptoms are cultivar specific, they specified that Forest Pansy, Appalachian, and Burgundy Hearts cultivars and C. chinensis cultivars are least affected by VSD symptoms, while bareroot C. canadensis and the cultivars Rising Sun, Black Pearl, and Ace of Hearts are most affected by VSD. Recent research findings in Tennessee indicate that redbud cultivars with yellow-colored foliage and papery leaf texture are more susceptible to VSD than those with dark green or purple foliage and thick, leathery leaves (Baysal-Gurel and Liyanapathiranage 2023). The fact that some of the least susceptible cultivars identified by respondents also possess these resilient traits supports the accuracy of their observations (Kidwell-Slak and Pooler 2018). Furthermore, the susceptibility of cultivars can vary depending on the region of redbud production, as some cultivars that have shown moderate tolerance to VSD in Tennessee were found to be susceptible in North Carolina (Chen H, personal communication). Different environmental factors and nursery management practices may contribute to the susceptibility of certain cultivars to VSD in different regions.

Other crops.

Fifty-six percent of respondents have observed the symptoms of VSD on ornamental plants other than redbud. The survey results show that VSD symptoms were observed in dogwood by 46% of respondents, in maple by 33%, in black gum by 9%, and in magnolia, flowering cherry, and tulip poplar by 4% each. Respondents observed VSD symptoms on other crops with a frequency of 6% in both 2017 and 2018, 16% in 2019, increasing to 27% in 2020, then decreasing to 17% in 2021, and rising again to 28% in 2022. Thirty-three percent of respondents mentioned dying from the top, and plant death is the unique symptom observed in these other crops compared with 22.3% of respondents who observed wilting, scorching, or yellowing. According to current observations, ornamental plants belonging to more than 25 genera are included in the host list for VSD (Liyanapathiranage et al. 2025). However, recent findings suggest that the updated host list could be vastly extended beyond what we currently know (Bily D, personal communication). It was interesting to uncover that the respondents had knowledge regarding the expansion of the VSD host range through their years of experience, even though most scientific research on the topic is still in progress.

Business information.

The majority of respondents (90%) purchased redbuds for their production. Among them, 50% of respondents made purchases in-state and 79% of respondents purchased redbuds from out of state. According to the responses, redbuds were mostly sourced from Tennessee (35%), followed by Oregon (21%), North Carolina (12%), and Virginia (9%), which are leading producers of redbuds in the United States. The remaining redbuds (23%) were sourced from other states.

Over three-quarters of respondents purchased liners, followed by one-third who bought 2-year-old plants, and 4% each, who bought bare root plants, 2-inch calipers, and seeds. Seventy-two percent of growers sold or shipped their redbuds out of state, while 28% of growers sold redbuds in state. According to the responses, growers sold 15,895 ball and burlapped plants with a value of $1,748,400, 9075 container plants with a value of $793,500, and 8500 bareroot plants with a value of $85,000. The total value of all plants sold in 2022 was $2,626,900. The average annual gross income of a nursery grower was around $2,583,853 from woody ornamental production, and redbud sales income was around 7.8% on average.

Demographic information.

According to the respondent’s ages, the majority were in the age group of 55 to 65 years (40%), followed by those older than 65 years (20%), 45 to 54 years (16.7%), and 35 to 44 years (3.3%); 10% preferred not to disclose their age. In the survey, respondents were asked to indicate their level of education. Most of the respondents (63.3%) had a college degree, followed by 20% with a high school degree and 10% with a master’s degree. The rest had some high school education (3.3%) or preferred not to say. According to the results, majority of respondents (60%) have more than 30 years of experience in nursery industry. Additionally, 20% of growers have 21 to 30 years of experience, 6.7% have 11 to 20 years, 6.7% have 5 to 10 years, and the remaining 6.7% have less than 5 years of experience.

Management practices.

The majority of the survey respondents (92.3%) were not involved in budding their redbuds. The smaller group of respondents who were practicing budding (7.7%) in their production setting could be producing their own cultivars. Because budding the plants requires wounding the stem tissue of a 1- to 2-year-old eastern redbud rootstock, this could be a potential stage during which VSD could be introduced into a healthy plant via the fresh wound. Additionally, if the bud sticks are taken from an already-infected mother plant, VSD could potentially be introduced to a healthy rootstock. This emphasizes the importance for redbud producers to accurately identify VSD symptoms to ensure VSD is not introduced into their production setting at this stage.

To understand growers’ pruning practices in redbud production nurseries, survey questions were crafted meticulously. The data reveal that 92.6% of participants engage in pruning their redbuds. Pruning predominantly occurs in May, June, and July, with notable activity also recorded in all other months except September and October. It is important to note that all surveyed growers use manual pruning methods. Pruning activities are aimed at maintaining the plants’ desired shape and size, which facilitates effective management practices. Nonetheless, it appears that some growers may not adhere strictly to the recommended pruning guidelines. Generally, pruning schedules are aligned with the flowering period of the plants; for instance, dogwood and redbud species are typically pruned postbloom in spring (Wade and Westerfield 2022). However, the survey indicates variability in the growers’ adherence to these timings. Considering the limited understanding of VSD biology, the impact of pruning on VSD progression remains unclear. Additionally, the influence of aftercare practices, such as wound dressing and the disposal of plant debris, on the spread of VSD within nurseries is not well understood. This underscores the need for further research to develop evidence-based guidelines that mitigate the risk of VSD transmission during pruning.

Respondents were asked whether they held redbud containers or bare root plants inside shade houses during production. Twenty-eight percent of respondents stated they used shade houses, while 72% did not. Among those using shade houses, ∼57% held their plants for 2 to 3 months, and 43% held their plants for a week or a few weeks. Although redbuds are generally shade tolerant, they become less tolerant to shade and competition as they mature, conditions that can be present in a greenhouse (Dickson 1990). Conversely, severe sunburn during summer months can damage leaves of some redbud cultivars, reducing plant vigor and increasing susceptibility to pests and diseases. These survey results indicate a need for further research to better understand optimal growing conditions for redbuds and to prevent issues such as VSD.

Nursery growers were surveyed about the irrigation methods used in redbud production. The majority of growers reported using drip irrigation (42.9%), followed by sprinkler irrigation (37.1%), hand watering (11.4%), and other methods (8.4%) such as overhead irrigation or irrigation using tractor. Regarding irrigation frequency, 35.3% indicated they irrigate as needed, 32.4% irrigate daily, 17.6% irrigate twice a week, 11.8% use other frequencies, and 2.9% irrigate every other week. Water requirements differ significantly between field conditions and container stages and are also influenced by the season and geographical location. In field conditions, plants often receive natural rainfall, which must be supplemented strategically to avoid overwatering or underwatering. Conversely, container-grown plants rely more heavily on scheduled irrigation, with early morning watering recommended to reduce evaporative losses (Nambuthiri et al. 2014). Seasonal variations, such as increased evaporation during hot summer months or reduced water needs during cooler periods, can affect irrigation practices. Geographical differences, including variations in climate, soil type, and water availability, also play a crucial role in determining the appropriate irrigation strategy for redbud production. Prolonged wet conditions on leaves can create a conducive environment for disease development. These survey results highlight the variability in irrigation practices among redbud growers, emphasizing the need for tailored irrigation recommendations to optimize plant health and prevent disease.

Sanitation.

Respondents were asked to indicate their choices regarding sanitation practices in redbud production (Fig. 2). According to the responses, more than 80% were not producing seedlings from seed, and 20% who did either clean or did not clean their seeds, with ∼9% in each group. Furthermore, follow-up questions were asked to identify whether the respondents are sanitizing their liners before planting and whether they are sanitizing the liners before storage. For both questions, only a few respondents, 13% and 4%, respectively indicated “yes.” As previously indicated, pruning is a management technique employed by most of the respondents. However, when asked whether they sanitize their pruning equipment, ∼30% of the respondents indicated that they do not. Root pruning is another management technique employed by some nursery producers to improve plant growth (Bartlett Tree Experts 2024). However, freshly pruned roots can serve as an entry point for soilborne pathogens (Łakomy et al. 2019). Therefore, when respondents were asked whether they sanitize or treat the roots after pruning, only 9% reported practicing this. Furthermore, 65% of the respondents were not sanitizing or cleaning their tools after budding, which indicates another management practice that may have been overlooked.

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Due to the difficulties with inoculation of the VSD causal agent(s), research is still underway to identify effective chemical treatments under natural infestation conditions (Baysal-Gurel et al. 2025). However, some growers are currently relying on their years of experience to select fungicides they have on hand to treat plants exhibiting VSD-related symptoms. This is evident from the 35% response rate to the survey question that inquired whether they apply any treatments to redbud plants showing VSD symptoms. Some of the most commonly mentioned fungicides were Subdue MAXX [mefenoxam (FRAC group 4)] and propiconozole 14.3 [propiconazole (FRAC group 3)] in a drench, Empress Intrinsic [pyraclostrobin (FRAC group 11)], Protect^DF [mancozeb (FRAC group M3)], Orkestra Intrinsic [fluxapyroxad (FRAC group 7) + pyraclostrobin (FRAC group 11)], Pageant Intrinsic [boscalid (FRAC group 7) + pyraclostrobin (FRAC group 11)], and Avelyo [mefentrifluconazole (FRAC group 3)]. Currently, the only available information on the most effective treatments to suppress VSD-related leaf scorching in seedlings, 3-year-old plants, and 2-year-old grafted cultivars are preventative foliar application of Postiva [pydiflumetofen (FRAC group 7) + difenoconazole (FRAC group 3)] at 20 fl oz/100 gal and Mural [azoxystrobin (FRAC group 11) + benzovindiflupyr (FRAC group 7)] at 7 oz/100 gal in 14-d application intervals (Liyanapathiranage and Baysal-Gurel 2023; Liyanapathiranage et al. 2023a, 2025).

To understand whether the respondents are currently dealing with other disease issues and whether they are using any chemical treatments to manage them, related questions were included in the survey. According to the responses, only 22% of them were applying treatments to redbuds to manage diseases such as Cercospora leaf spot and Phytophthora root rot diseases. In addition to well-established issues typically associated with redbuds, such as canker problems, recent research has identified novel pathogens affecting the redbud production in the United States, including root rot of redbud caused by Phytopythium vexans and crown and root rot on redbud caused by Calonectria cylindrospora, thereby enhancing our understanding of the challenges associated with redbud production (Liyanapathiranage et al. 2023b; Purdue University Extension n.d.; Subedi et al. 2025; Texas A&M AgriLife Extension Service n.d.).

Economic impact.

Nursery growers were asked to mention whether they had lost their redbud production last year, reason or reasons affected for the loss of redbuds, and the percentages of the losses. Respondents have lost redbuds mainly due to VSD (69.7%), followed by winter damage (19.3%), root rot (2.5%), and other reasons (8.5%). Although accurately distinguishing VSD symptoms is challenging, considering that most respondents have over 30 years of experience in the nursery industry, it is reasonable to assume that they possess the ability to differentiate these new symptoms from other issues they have encountered in plants over the years.

Also, the survey asked respondents to report the average loss percentage of redbud production last year, based on each production category. They have lost 25.2% of container plants worth $375,037, 24.8% of bare root seedling liners worth around $369,084, 22.1% of ball and burlapped plants worth $328,901, 20.9% of container seedling liners worth around $311,042, and 7% of bare root plants worth around $104,176 in 2023 due to VSD. Ornamental nursey producers are often involved in growing a diverse range of plant species within their operations. However, when they face heavy losses in a particular plant species—especially those are at the final stage of production—it becomes particularly challenging. These plants have already required significant investments in time, labor, and financial resources. Consequently, such losses can have an impact on the producers, in terms of both financial strain and overall business sustainability. At the end of the survey, respondents were asked how they anticipated their redbud production operations would change in the coming year. The results showed a cautious outlook: 46% of respondents believed production would decrease due to the challenges they have faced, while 39% had not yet made a decision regarding their production plans or expected it to remain the same, reflecting uncertainty in the market. On the other hand, 15% were optimistic, anticipating an increase in redbud production despite the ongoing difficulties.

The ordinal logistic regression model was used to estimate the probability of survey participants altering their redbud production based on their responses throughout the questionnaire. As shown in Table 2, when the demographic data were tested, the results revealed that the coefficients for education level did not show significant correlations. The growers in 55- to 65-year age category showed a significant and negative correlation at 5% significance level. The 25- to 34-year age category is the reference category for age variable. Being age 55 to 65 years decreases by 0.158 times the odds of deciding to increase production compared with the reference category of being age between 25 to 34 years old. When the experience levels were tested, over 30 years of experience in nursery production showed a significant correlation at the 10% significance level, indicating its influence on the decision to alter redbud production in the coming year. Nursery growers with 30 years of experience are less likely to increase redbud production next year. According to the odds ratio, redbud production decreases by 0.173 odds compared with growers having less than 5 years of experience. Nursery size has a positive and significant effect on redbud production behavior. The coefficient for nursery size was positive and significant at the 5% level. As nursery size increases, the odd ratio of increasing redbud production rise by 0.107 times, highlighting the influence on future production decisions. When the coefficients of redbud production stages in which VSD was observed by the respondents were tested, significant and negative correlations were found at 5% level for field production (−0.027) and landscape production (−3.414). Also, a significant and negative correlation at the 10% level was observed for pot-in-pot production (−4.134), compared with container production, which served as the reference group. If the field plants show VSD symptoms, increasing production shows 0.973 times lower odds compared with container plants. If pot-in-pot plants show VSD symptoms, growers show 0.034 times less odds to increase pot-in-pot production. Also, growers whose redbud landscape plants have VSD symptoms show 0.016 lower odds to increase redbud production in the future. When the coefficient of redbud container production category was tested, the results were negative and significant at the 1% level. This finding indicates that growers who produce container plants were 0.738 times less likely to increase redbud production in the future. Redbud production loss due to VSD compared with no loss was negative and statistically significant at the 5% level. Growers who had lost redbud plants due to VSD were 0.028 times less likely to increase redbud production next year. Findings from this analysis were useful in understanding the factors that most likely contributed to the decision-making of survey respondents regarding future redbud production. As described above, demographics, nursery production dimensions, and VSD acted as key factors influencing the decision to alter redbud production next year, particularly toward a decrease in production.

Table 2. Estimated ordered logit model coefficients indicating the relative importance of nursery growers demographic and redbud production factors to change the redbud production next year based on survey data sample (n = 48).

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