Final report for LNE13-324
The development of new native shrubs for growers will help to replace lost sales of invasives and may even generate new revenue. The goal of this project was to develop commercially viable propagation and production systems for novel native shrubs and to have growers adopt these native species as alternatives to invasives.
Twelve growers and four extension educators attended an orientation workshop to learn about novel native shrub crop alternatives to invasives. Five nurseries expressed interest in trialing the new native shrub crops and all five nurseries received starter plant material in 2014.
Propagation and production research was conducted for 6-10 novel native taxa. Two peer-reviewed journal articles, six trade articles, two extension articles, a native shrub production manual, and three fact sheets were developed based on the results from this project. To reach a larger cross section of the green industry, over 30 educational presentations across five states (CT, MA, NH, NY, RI) on this grant project were delivered at various green industry association meetings, conferences, and symposia.
A twilight meeting with the five participating nurseries was held on February 20, 2015 at the University of Connecticut C.R. Burr Teaching Nursery. At this meeting, one of the key growers presented their experiences (propagation, container growing, and marketing) with several of the native shrub taxa. A second twilight meeting of participating nurseries was held on February 7, 2017 where growers received the native shrub production manual developed by the P.I. Also at this meeting, growers provided the requested verification feedback, which included information about number of plants sold since 2014 and number of plants in production inventory.
By the end of this project, three wholesale nurseries had added four native shrubs to their production lines and had generated plant material worth $759,690. The value of these plants exceeds the $500,000 in lost revenue from invasive shrubs.
Historically, the American landscape has been filled with non-native plants originating largely from Europe and Asia. Unfortunately, many of the same characteristics that make non-native plants successful ornamentals in the landscape also may make them potentially aggressive in natural environments. Plant invasions upset ecosystem dynamics by preventing the establishment of seedlings belonging to native flora and altering various parameters of soil chemistry to the further detriment of indigenous plants. Concern over the negative ecological effects of certain non-native species has prompted many states to consider banning the sale of these species.
The nursery industry is facing the loss of some of its most important shrub crops due to their invasive tendencies. Two such shrub crops, which have been popular ornamental landscape plants for many decades, are Japanese barberry (Berberis thunbergii) and winged euonymous (Euonymus alatus). Both Japanese barberry and winged euonymus have been banned in Massachusetts and New Hampshire and two counties in Long Island, NY has legislation in place that will ban these species in 2016. The Connecticut Nursery and Landscape Association enacted a voluntary ban on high fruiting barberry cultivars in 2010.
One large wholesale grower in Connecticut reports that sales of Japanese barberry are down 63% from 2009. In 2009 the nursery sold 13,469 container units, which generated sales of $129,450 and in 2012 the nursery sold 4896 container units, which generated sales of $48,031. Other major wholesale nursery producers indicate similar declines in sales for invasive shrubs. This is a significant loss for growers since the annual wholesale value of just one popular invasive shrub, Japanese barberry, is $28.5 million in the United States according to the 2009 Census of Horticultural Specialties. Wholesale nurseries and growers need to replace these invasive shrub crops with something new to maintain profitability. The development of new native shrubs for growers will help to replace lost sales of invasives and may even generate new revenue.
Solution and Benefits
A widely recognized solution to the loss of invasive shrubs is the increased use of native shrubs for landscaping. Native plants represent the best alternative to invasives and growers can use new native plant crops to replace invasives they can no longer produce.
Native shrubs are a great alternative to invasives because: 1) they are not invasive; 2) they integrate landscapes with surrounding natural flora; and 3) they support native insects and wildlife. Gardening consumers indicated a strong desire in using native plants in landscaping according to a 2010 Garden Writers Association survey. Additional surveys showed that landscape architects and master gardeners would like to use more native plants, but have found that a broad palette of native plants is not readily available from growers.
For growers to capitalize on the native market, they must expand their product lines by adding new species. Landscape plants are often used in locations with challenging environmental conditions including reflected light, high temperatures, inadequate water supply, infertile soil, road salt and pedestrian pressure. Expanded use of native species will be most successful if growers, landscapers and consumers know which native species will perform well in challenging landscape situations where invasives have typically been used. Use of poorly adapted native plants in landscape situations produces unsatisfactory results, which diminishes peoples desire to expand their use of natives. Research I have conducted at the University of Connecticut has identified 10 new native shrubs that are adaptable and able to directly replace invasives in landscapes. Each plant offers gardeners multiple ornamental attributes such as interesting summer foliage, refined habit, edible fruits, attractive flowers and respectable fall foliage color. These native shrubs have been unused in the landscape because their landscape adaptability was unknown and because production systems have not been developed.
Some native shrubs are already being successfully produced by the nursery industry and are widely used in the landscape, such as winterberry holly (Ilex verticillata), summersweet (Clethra alnifolia) and arrowwood viburnum (Viburnum dentatum). One large Connecticut grower produced 11,000 winterberry hollies in 2011, which generated more than $150,000 in sales. Growers must be able to produce these newly identified native shrubs using production systems whose efficiencies are on par with those already used to produce native shrubs like winterberry holly. The goal of this project was to develop commercially viable propagation and production systems for these novel native shrubs.
Research and educational approach
This project combined research trials to optimize production of identified novel native shrubs and comprehensive education about these crops and growing them economically. An orientation workshop at UConn was held for growers to learn about the novel adaptable native shrubs. Increasingly, retailers, landscape contractors and designers look to growers for information about how and where to use the plants they grow in the landscape. Therefore the orientation workshop not only introduced growers to the new native shrub crops, but also to their landscape uses. The workshop began with interactive presentations containing color photos and numerous concrete examples illustrating how to use the new native shrubs in appropriate landscaping situations. Workshop attendees received a guided tour of the native shrub plantings on the UConn campus. During the workshop, information was obtained from attendees for use in prioritizing research experiments and developing experimental treatments. Attendees assisted in refining research hypotheses by providing responses to questions such as: (1) What type of propagation system is preferred (2) What is a desirable market size (i.e. 1-gallon, 2-gallon or 3-gallon and (3) What cultural practices will be important for producing market quality plants in a reasonable time frame.
The two key growers received liners and grew plants on at their nursery and kept crop records on each species. The project leader met with key growers to help develop propagation protocols for each native species using the original plants as the source of propagules. Grower meetings were held where growers gained knowledge about production of new native shrubs directly from the experiences of the key growers. Attendees of workshops received a copy of the native shrub manual written by the project leader. Findings from this project were disseminated through publications in peer-reviewed scientific journals and trade publications.
Five wholesale nursery growers will add six native shrubs to their production lines and market them as adaptable landscape shrubs to replace $500,000 in lost revenue from invasives.
The hypothesis is that commercially viable propagation and production systems can be developed for the identified native shrub replacements, which are American filbert (Corylus americana), beaked filbert (Corylus cornuta), buttonbush (Cephalanthus occidentalis), creeping sand cherry (Prunus pumila var. depressa), elderberry (Sambucus canadensis), grey dogwood (Cornus racemosa), northern bush honeysuckle (Diervilla lonicera), round leaf dogwood (Cornus rugosa), sweet fern (Comptonia peregrina) and sweet gale (Morella gale).
Cutting propagation is often preferred over seed propagation because cuttings produce marketable sized plants in a shorter amount of time and the plants produced have uniform phenotype or appearance. Uniformity in appearance is important to nursery growers because most of their customers expect individuals of a species to look and perform similarly.
Propagation by softwood stem cuttings was evaluated for the following native shrub species: Ceanothus americanus (New Jersey tea), Comptonia peregrina (Sweet fern), Corylus cornuta (beaked filbert), Eubotrys racemosa (sweetbells), Lonicera canadensis (American fly honeysuckle), Myrica gale (sweet gale), Prunus pumila var. depressa (creeping sand cherry), Vaccinium staminium (deerberry), Viburnum acerifolium (maple leaf viburnum), Viburnum lantanoides (hobblebush). Softwood stem material was collected from mature plants and processed into cuttings 10 to 15 cm in length with two to three nodes. C. peregrina cuttings were 1-3" in long shoots removed from rhizomes soon after emergence. Cuttings were wounded and dipped in talc-based, IBA rooting hormone [Hormodin (OHP Inc., Mainland PA)] at 0 ppm, 1000 ppm (Hormodin #1), 3000 ppm (Hormodin #2) or 8000 ppm (Hormodin #3). Dipped cuttings were inserted into 1.3-L plastic flats filled with medium composed of two parts Canadian sphagnum peat moss, one part horticultural-grade vermiculite and one part horticultural-grade perlite. Flats of cuttings were held on a polyhouse bench under intermittent mist that provided 10 s of mist every 6 min. After 8 weeks, rooting success was evaluated and the optimal propagation conditions are reported in Table 1.
Lonicera canadensis, Corylus cornuta, Viburnum acerifolium are native shrubs useful for northeastern and north-central US landscapes with dry, shaded conditions. Objectives of this study were to evaluate the impact on growth in containers of 1) growth media amended with expanded shale at 3 rates; 2) 2 rates of controlled-release fertilizer; and 3) pruning of maple leaf viburnum. Plant height, width, size, and number of shoots were measured.
Media and fertility study. Plants used in this experiment were supplied from the propagation studies of Cartabiano and Lubell (2013). This experiment was first conducted in 2013, and was repeated in 2014. Two-year old uniform liners of beaked filbert and maple leaf viburnum grown in 307-ml containers were transplanted into 3-L (trade #1) containers on 20 May 2013 and 19 May 2014. Liner plants were approximately 26 cm tall and 18 cm wide at time of transplanting. American fly honeysuckle grew more slowly in container culture than the other species, therefore smaller containers were used and the same plants were carried through from 2013 to 2014. On 20 May 2013, two-year old uniform liners of American fly honeysuckle grown in 106-ml square containers were transplanted into 307-ml square containers, and on 19 May 2014, they were transplanted into 3-L containers. At transplanting, liners were approximately 10 cm tall and 9 cm wide in 2013 and 30 cm tall and 32 cm wide in 2014. Plants were overwintered during the 2013-2014 winter (November to April) in a white polyethylene-covered hoop house and irrigated by hand as needed. In 2014, American fly honeysuckle plants were shaded with black woven polypropylene material to provide 50% of maximum irradiation. The growth media was 4 pine bark: 2 peat moss: 1 sand (by volume) amended with dolomitic lime at 0.5 kg/m3. Expanded shale of particle size range 10 to 15 mm diameter (Bigelow Brook Farm, Eastford, CT) was then added to the media at rates of 0%, 20%, and 50% (by volume) to create three experimental growth media. Air-filled porosity, total porosity, container capacity, bulk density and pH were measured on three samples of each experimental growth media (Table 1). The physical parameters of the growth media were determined according to Bragg and Chambers (1988) and Niedziela and Nelson (1992). Pore electrical conductivity was recorded with a WET Sensor (Delta-T Devices Ltd., Cambridge, UK). Controlled-release fertilizer (CRF) 15N-3.9P-10K (OsmocoteÒPlus, 8 – 9 month formulation; Scotts, Marysville, OH) was applied at time of transplanting as topdressing at the rate of 1g N or 2.5 g N per 3-L container and 0.25 g N or 0.625 g N per 307-ml container. The higher rate of N used was equivalent to the medium recommended rate on the fertilizer product label, and the lower rate of N used was slightly less than the low recommended rate on the product label. Irrigation was provided during the growing seasons by trickle emitters on an as-needed basis for both years of the study.
Pruning study. This experiment was repeated for two years, in 2013 and 2014.
Uniform liners in 307-ml containers of maple leaf viburnum, supplied from the propagation studies of Cartabiano and Lubell (2013), were transplanted to 3-L containers on 20 May 2013 and 19 May 2014. The growth media was 4 pine bark: 2 peat moss: 1 sand (by volume) amended with dolomitic lime at 0.5 kg/m3. The same CRF used for the media and fertility study was applied at time of transplanting as topdressing at the rate of 17 g per container. On 21 May 2013 and 22 May 2014 plants were selected at random and pruned to a height of 12 cm or left unpruned. The average initial height of unpruned plants was 38 cm. Irrigation was as described for the media and fertility study.
Experimental design and data analysis. For both studies the experimental design was a randomized complete block design with 10 replications and the experimental unit was a single containerized plant. Species were randomized separately for the media and fertility study. Data was collected during the second week of August in both years. Plant height and width and number of shoots were measured for all plants. Plant width was measured twice, at right angles to each measurement, and averaged. Plant size was calculated as the product of height and two perpendicular widths. Pruning study plants were rated visually using a scale of 1 to 3, where 1 represented an asymmetrical plant, 2 represented a partially symmetrical plant, and 3 represented a completely symmetrical plant. Data were subjected to analysis of variance using the PROC MIXED procedure and mean separation using Fisher’s least significant difference test (P £ 0.05) using SAS (version 9.2 for Windows; SAS Institute, Cary, NC).
Growth of Eubotrys racemosa, Lonicera canadensis and Viburnum lantanoides in nursery trade #1 containers under shade levels of 0%, 40%, or 70% was evaluated. Plant height, width, size, number of shoots and leaves, and shoot and root dry weight, and chlorophyll fluorescence were measured. In addition CIELAB color measurements were made.
This study was conducted outdoors in a gravel-surfaced container nursery at the UConn Plant Science Research and Education Facility in 2015 and repeated in 2016. Two-year old uniform liners of american fly honeysuckle, hobblebush, and sweetbells grown in 0.32-qt containers were transplanted into 3.2-qt (trade #1) containers on 5 May 2015 and 28 Apr. 2016. At time of transplanting liner plants of american fly honeysuckle averaged 17 inches tall, 14 inches wide and had 12 shoots; hobblebush averaged 8 inches tall, 9 inches wide, and had 3 shoots and 10 leaves; and sweetbells averaged 8 inches tall, 5 inches wide and had 9 shoots. The growth medium was 4 parts aged pine bark (Fafard Inc.): 2 parts Canadian sphagnum peat moss (Fafard Inc.): 1 part sand amended with dolomitic lime at 24 oz/yard3. Following transplanting, containers were topdressed with controlled release fertilizer (Osmocote Pro 20N-1.7P-5.8K 8 to 9 month formulation, Everris NA Inc., Dublin, OH) at 0.4 oz per plant. Irrigation was provided during the growing season by trickle emitters at the rate of 0.85 qt per day. Shade was provided by covering sections (16-ft long) of metal hoop house (8-ft high, 48-ft long, and 17-ft wide) with woven polypropylene cloth. Shade densities provided by the cloth were verified in April using a line quantum sensor (LI-COR) and a quantum photometer (LI-189, LI-COR) and were determined to be 70% (≈390 µmol×m-2×s-1 PAR) and 40% (≈765 µmol×m-2×s-1 PAR). No shade cloth was provided for the full sun treatment. The experimental design was a split-plot with shade as the fixed main plot. Within each main plot, there was a randomized complete block arrangement with 10 blocks each comprised 1 plant of each species. Plants were placed in shade from 14 May to 12 Aug. in 2015 (90 d) and 3 May to 8 Aug. in 2016 (97 d).
Chlorophyll fluorescence (Fv/Fm) was measured biweekly from 26 May 2015 (week 21) to 4 Aug. 2015 (week 31) using a fluorometer [Plant Efficiency Analyzer (PEA); Hansatech Instruments Ltd., Norfolk, England) for four randomly selected plants per species per shade level. For each plant, three Fv/Fm measurements were taken using different leaves of similar age, and these values were averaged for each plant. The same leaves (marked with small tags) and plants were recorded over the 10-week measuring period. Leaves were dark adapted for 15 min using the manufacturer’s leaf clips prior to measuring. Soil temperature was measured biweekly from week 21 to week 31 in 2015 and 2016 using a moisture meter (WET Sensor type WET-2 and HH2; Delta-T Devices, Cambridge, England) for 12 randomly selected plants (four plants per species) per shade level. On 2 Aug. (week 31) of 2016 leaf color was analyzed for four randomly selected plants per species per shade level using a CR-400 Chroma Meter connected to a DP-400 data processor (Konica Minolta Sensing Americas, Inc., Ramsey, NJ). For each plant, three Commission Internationale de l'Eclairage, lightness, red-green axis, blue-green axis (CIELAB, Vienna Austria) measurements were taken using different leaves of similar age, and these values were averaged for each plant. Lightness (L*), red-green axis (a*), and blue-green axis (b*), were measured at the mid point between the distal and basal leaf ends. Leaf midribs were excluded from the sampling area. The colorimeter was calibrated at illuminant C with a white standard. Due to the slightly translucent nature of the plant leaf tissue, a standard white background was placed behind each leaf when a CIELAB measurement was taken (Little, 1964). In addition to the CIELAB coordinated value, L*, the coordinates of hue angle (tan -1b*/a*) and chroma (a*2+b*2) were calculated from a* and b*. During the second week of August of both years, plants were destructively harvested and plant height and width, number of shoots and shoot and root dry weights were recorded. The number of leaves was counted for hobblebush. Plant height was measured from substrate surface to the apex of the foliage. Plant width was measured twice, at right angles to each measurement. Plant size was then calculated by multiplying height x width 1 x width 2. Root harvest was accomplished by un-potting the plants, shaking the potting media from the roots and washing the roots. Shoots and roots were dried at 70 °C for »72 h and weighed.
Plant harvest and leaf color data were subjected to analysis of variance (PROC MIXED) and mean separation using Fisher’s least significant difference test (P ≤ 0.05) using SAS (Version 9.4 for Windows; SAS Institute, Cary, NC). There was no significant difference between years, so the plant harvest data from both years was combined for statistical analysis.
Stem cutting propagation studies were completed for the native shrubs listed in table 1.
Native species Time of year IBA ppm Percent rooting
Ceanothus americanus June 3000 50-60
Comptonia peregrina (1-3" shoots from rhizomes) April, May 1000, 3000 100
Corylus cornuta June, July, Aug. 3000 80-90
Eubotrys racemosa June, July 0, 1000, 3000 100
Lonicera canadensis May, June 3000 45-50
Myrica gale June 3000 90
Prunus pumila var. depressa June, July 3000 90
Vaccinium staminium June 1000, 3000 85-90
Viburnum acerifolium (two-node cuttings) June, July, Aug. 0, 1000, 3000 100
Viburnum acerifolium (single node cuttings) July 3000, 8000 65-80
Viburnum lantanoides June 3000, 8000 80-85
Typical nursery potting media is a 4:2:1 bark:peat:sand mix. This mix has worked well for numerous shrub crops and species of interest in this project including, Myrica gale, Diervilla lonicera and Prunus pumila var. depressa. Two production studies were conducted to optimize container growth for species that I had suspected may require modified container production conditions.
Ex-panded shale added to growth media composed of 4 parts pine bark, 2 parts peat moss, and 1 part sand did not improve growth for these species, and significantly larger plants of American fly honeysuckle were produced in the control media (lacking expanded shale) than in the amended media. Over a 2-y production cycle, the higher fertility rate of 2.5 g nitrogen (N)/pot produced American fly honeysuckle plants that were larger and had more shoots than did American fly honeysuckle plants that received 1.0 g N/pot. For beaked filbert, the higher fertility rate can produce greater growth, but may not do so every year. Fertility rate did not affect growth of maple leaf viburnum. Plants of maple leaf viburnum that were pruned after transplanting into trade #1 containers had visual quality ratings 2 times greater than unpruned plants. Pruned maple leaf viburnum had equivalent plant height and width and a more symmetrical and full appearance than did unpruned maple leaf viburnum plants.
Lonicera canadensis grown under 40% or 70% shade were larger, had a greener hue angle, and higher chlorophyll fluorescence (Fv/Fm) than plants grown in full sun. Throughout the study period, Fv/Fm values for full-sun Lonicera canadensis were 0.6 or below, indicating plants were stressed. Viburnum lantanoides in 40% and 70% shade were wider, had more leaves, and enhanced foliage color compared with full- sun plants. Viburnum lantanoides in 70% had the highest Fv/Fm values at 0.78 or higher across the study period. For Eubotrys racemosa , plant width increased as shade level increased. Even though Eubotrys racemosa in 70% shade were wider and larger, they lacked density and had a less appealing habit than 40% shade and full-sun plants.
For a native plant to be considered a viable commercial crop for general wholesale nurseries it must be able to be propagated with at least 70% propagation success. Growers focusing on production of only native plant material may find lower percent rooting to be acceptable. Eubotrys racemosa and Viburnum acerifolium, from cuttings with a minimum of two nodes, were the easiest shrubs to propagate and have the most obvious potential to become mainstream nursery crops. Myrica gale and Prunus pumila var. depressa were also very easy to propagate from cuttings at commercially viable rates. Comptonia peregrian propagated from young shoots (1-3") emerging from rhizomes are easily rooted. Corylus cornuta, Vaccinium staminium and Viburnum lantanoides could be rooted at rates above 80%, and likely can become commercial crops. Without development of improved propagation methods for Ceanothus americanus and Lonicera canadensis, it is unlikely that these two species will be viable crops for large wholesale growers, but may still hold promise for specialty native plant producers. One propagation technique that has proven to be critical in dramatically increasing propagation success with some of the native species (Corylus cornuta, Viburnum acerifolium) is overwintering rooted cuttings in their propagation flat and repotting in spring. Leaving cuttings undisturbed for the first overwintering period will likely significantly improve propagation success with other native shrubs species such as Ceanothus americanus and Lonicera canadensis.
We have found that Lonicera canadensis, Corylus cornuta, and Viburnum acerifolium can be successfully grown in containers for the retail nursery market. All 3 species can be grown well in a 4-part softwood bark, 2-part peat moss, and 1-part sand growth media and a controlled-release fertilizer at low to medium recommended rates (Figure 1). Maple leaf viburnum benefits from early season pruning in container culture. We have observed that Lonicera canadensis and Corylus cornuta develop more slowly than other nursery crops early on, but they grow quickly once established in containers. Our experience indicates that shade is beneficial for container production of Lonicera canadensis.
Of the three study species, Eubotrys racemosa might be the easiest plant for growers to incorporate into production because it propagates readily from stem cuttings and can be grown in full sun to 40% shade. Viburnum lantanoides and Lonicera canadensis may present more challenges for growers because Viburnum lantanoides requires considerable shade to grow and Lonicera canadensis is more difficult to propagate.
Education utilized a combination of lectures to small groups, feedback surveys, and consultation visits to nurseries. Small group meetings were effective at promoting discussion about priorities for native shrub research and market drivers for native plants. Surveys were effective at identifying changes in grower knowledge and behavior.
Reported in the research sections.
Twelve growers and four extension educators attended the orientation workshop about developing novel native shrub crops as alternatives to invasive species for the green industry held in October 2013. The verification survey of the orientation workshop showed that grower understanding of native shrub features, adaptability, and use as invasive alternatives increased from an average of 2.8 (on a scale of 1 to 5) before the orientation workshop to an average of 4.6 after the orientation workshop.
This grant proposal planned for two key growers to trial plants during the grant period. However, since several growers had expressed strong interest in the native taxa presented on at the orientation workshop, I was able to recruit five nurseries to trial select native taxa starting in 2014. The five nurseries received starting material for two to five different native taxa in 2014.
In 2014 I visited two participating growers and observed their facilities and exiting shrub production.
In 2015 I visited two participating growers and observed several of the native trial species in various stages of propagation and container production. I visited Canterbury Horticulture on June 23, 2015 and Prides Corner Farms on November 19 2015. I advised growers on several aspects of timing of taking cuttings and propagation media porosity.
The growers from the participating nurseries expressed a strong willingness to share their experiences with the native taxa over time. At a meeting of participating nurseries on February 20, 2015, one of the key growers presented on his experiences with propagation, container growing, and marketing, of the native taxa received. Also at this meeting held at UConn C.R. Burr Teaching Nursery, I presented preliminary findings from propagation trials and the group toured the nursery to examine dormant propagation stock.
The manual includes information about propagation and container production for 12 native shrub species for use as alternatives to invasives in challenging landscapes.
At this meeting participating growers provided the requested verification information about the number of plants currently in production inventory and the number of plants sold since 2014. Growers received the native shrub production manual developed by the P.I.
In 2016, I visited all five of the original participating nurseries to consult on aspects of propagation and container production for the trial taxa.
Milestone Activities and Participation Summary
The verification survey of the orientation workshop showed that grower understanding of native shrub features, adaptability, and use as invasive alternatives increased from an average of 2.8 (on a scale of 1 to 5) before the orientation workshop to an average of 4.6 after the orientation workshop. The final project verification survey indicated that growers added new native species to their production lines, which demonstrates a change of behavior impact for this project. The final verification survey indicated that from 2014 to 2017, three Connecticut wholesale growers increased production numbers of four native species by 200%.
Performance Target Outcomes
Add 6 native shrubs to production lines
replace $500,000 in lost revenue
increased or maintained production revenue
Added 4 native shrubs to production lines
50,646 plants were produced worth $759,690
production revenue was increased by $259,690
Three wholesale nursery growers added four native shrubs to their production lines and are marketing them as adaptable landscape alternatives to invasive shrubs. During the duration of this project growers produced new native shrubs worth $759,690. The value of these plants exceeds the $500,000 in lost revenue from invasive shrubs. Five nursery growers received the verification survey and four of them responded. One of the respondents did not add new native shrubs to production lines.
Additional Project Outcomes
- New England Native Shrubs for Sustainable Landscapes (Manual/Guide)
- Production of Three Eastern U.S. Native Shrubs: Effects of Auxin Concentration on Rooting and Shade Level on Container Plant Growth (Peer-reviewed Journal Article)
- Optimizing container production of American fly honeysuckle (Lonicera canadensis L.), beaked filbert (Corylus cornuta Marsh.), and maple leaf viburnum (Viburnum acerifolium L.) (Peer-reviewed Journal Article)
- Ten Tough New Native Shrub Alternatives for Barberry and Burning Bush (Fact Sheet)
- New England Native Shrub Replacements for Japanese Barberry and Winged Euonymus (Fact Sheet)
- Challenges to developing the market for native shrubs (Fact Sheet)