Winston Dunwell1, Dwight Wolfe1, Robert McNiel2, Sharon Bale2, and Dewayne Ingram2
1Research and Education Center, University of Kentucky, Princeton, KY 42445
2Department of Horticulture, University of Kentucky, Lexington, KY 40546
Index Words: Hydrangea, cut flowers, irrigation, pruning
Nature of Work:
Cut flowers from field-grown Hydrangeas are a potential alternative source of income for Kentucky growers, and early production can increase financial returns on one's investment. Typically, H. macrophylla cultivars are grown for the cut flower market; while other species such as: H. arborescens, smooth hydrangea; H. paniculata, panicled hydrangea; and H. quercifolia, oakleaf hydrangea; have been grown as landscape plants (Armitage, 1993; Bale, 1999). Interest has been expressed in H. arborescens and H. paniculata as fresh cut and dried flowers by wholesale distributors (Trimble, 2000). Expansion of the cut flower production mix to include these Hydrangea species could create specialty-niche markets for Kentucky growers.
A Hydrangea cut-flower cultivar trial was established at the University of Kentucky Research and Education Center, Princeton, KY, in the Spring of 1998 (Dunwell, et al, 1999; Dunwell, et al, 2000; Wolfe and Dunwell, 1999). The planting consisted of twelve plants each of nine cultivars allocated to 12 rows (blocks) in a randomized block design. The nine cultivars included one H. aborescens cultivar, 'Annabelle'; one H. quercifolia cultivar, 'Alice'; and seven H. paniculata, panicled hydrangea, cultivars, 'Boskoop'; 'Pink Diamond'; 'Unique'; 'Kyushu'; 'Tardiva'; 'Pee Wee'; and 'White Moth'. A planting with trickle irrigation was established in the Spring of 1999. It consists of six H. paniculata cultivars, 'Pink Diamond', 'Unique', 'Kyushu', 'Tardiva', 'Pee Wee', and 'White Moth', allocated to 8 rows (blocks) in a randomized block design. In the Autumn of 2000, alternate rows of each planting were pruned to ground level. The number of stems per plant, stem length, and bloom length were recorded.
Results and Discussion:
'Alice', 'Annabelle' and 'Boskoop' where not included in the irrigated planting. Pruning significantly affected the average number of stems per plant for all cultivars except for 'Annabelle' and 'White Moth', which showed no significant response to pruning (Table 1). 'Kyushu' and 'Pee Wee' produced largest numbers of stems when pruned and irrigated. Not pruning the plants resulted in stems less than the 36 inches in length needed for the cut-flower market (S. Bale, 1999).
Pruning 'White Moth' under irrigation resulted in vigorous long stems (Table 2) that tended to continue growing and not produce blooms. Plants of 'White Moth' that were pruned and not irrigated also did not produce any blooms. H. quercifolia flowers on year-old wood (D. Bir, 2000) and, as expected, the pruned plants of 'Alice' did not flower (Table 3).
'Kyushu' was the only cultivar that produced significantly longer blooms when not pruned. This was true for both the irrigated and non-irrigated plantings. A limiting factor to marketability of 'Kyushu' may be the observation that blooms do not have as many showy sterile flowers as 'Pink Diamond', 'Unique', or 'Pee Wee'.
Significance to Industry: Under the conditions found in this study 'White Moth' does not appear to be a good H. paniculata cultivar for hydrangea cut-flower production. All other Hydrangea cultivars show potential for producing white fresh and tan dried cut-flowers. The 'Kyushu' characteristics of producing large numbers of stems (115) and longer blooms (8.7 inches) when not pruned and irrigated needs to be studied further. Modifying production practices could result in a plant that produces large blooms and has a stem of adequate length for a specialty market.
Literature Cited:
Armitage, A.M. 1993. Specialty cut flowers. 1st ed. Timber Press, Portland, Ore.
Bale, Sharon. 1999. Personal communication.
Bir, Dick. 2000. Pruning Hydrangeas. 22 June 2001.
http://www.ca.uky.edu/HLA/Dunwell/hydprun.html
Dunwell, Winston, Dwight Wolfe, and June Johnston. 2000. Hydrangeas for Cut Flowers: 1999
Observations. UK Nursery and Landscape Program: 1999 Research Report, PR 422:19.
Dunwell Winston, Dwight Wolfe, and June Johnston. 1999. Hydrangeas for Cut Flowers: Early
Observations. Nursery and Landscape Program 1998 Research Report PR-409:37.
Trimble, Ann. 2000. Personal communication.
Wolfe, Dwight E. and Winston C. Dunwell. 1999. Production of Cut Flowers from Field-grown Hydrangeas. HortScience vol 34(3): 476 Abstract #202.
Table 1. Number of stems per plant as affected by pruning and cultivar for irrigated and non-irrigated plantings of Hydrangea cultivars at UKREC, Princeton, KY.
| Cultivar | Pruned | Not Pruned | Mean | Pruned | Not Pruned | Mean |
| Non-Irrigated Planting | Irrigated Planting | |||||
| Average Number of Stems Per Plant | ||||||
| Alice | 0.0 | 23.4 *1 | 13.4 | |||
| Annabelle | 14.2 | 16.7 ns | 15.4 | |||
| Boskoop | 7.8 | 29.0 * | 19.3 | |||
| Kyushu | 11.3 | 54.0 * | 32.7 | 14.8 | 115.5 * | 65.1 |
| Pee Wee | 5.0 | 24.3 * | 14.7 | 12.8 | 112.0 * | 62.4 |
| Pink Diamond | 11.2 | 41.3 * | 26.3 | 19.8 | 49.5 * | 34.6 |
| Tardiva | 7.5 | 21.7 * | 14.6 | 12.0 | 95.8 * | 53.9 |
| Unique | 18.2 | 37.0 * | 27.6 | 24.8 | 86.3 * | 55.5 |
| White Moth | 0.3 | 0.8 ns | 0.5 | 1.3 | 4.3 ns | 2.8 |
| Mean | - - | - - | 18.6 | - - | - - | 45.7 |
| LSD (P=0.05) | - - | - - | 7.4 | - - | - - | 20.9 |
1 "*"and "ns" indicate that mean in previous adjacent column is either significant or not significant, respectively, at the 0.05 probability level from mean in column.
Table 2. Average stem length as affected by pruning and cultivar for irrigated and non-irrigated plantings of Hydrangea cultivars at UKREC, Princeton, KY.
| Cultivar | Pruned | Not Pruned | Mean | Pruned | Not Pruned | Mean |
| Non-Irrigated Planting | Irrigated Planting | |||||
| Average Length (inches) per Stem | ||||||
| Alice | - - | 10.0 | 9.9 | |||
| Annabelle | 20.5 | 18.4 ns1 | 19.5 | |||
| Boskoop | 30.2 | 16.1 * | 22.5 | |||
| Kyushu | 41.4 | 17.3 * | 29.4 | 54.3 | 17.0 * | 35.6 |
| Pee Wee | 43.3 | 15.3 * | 29.5 | 52.4 | 14.9 * | 33.7 |
| Pink Diamond | 35.8 | 16.0 * | 25.9 | 39.2 | 17.1 * | 28.1 |
| Tardiva | 38.2 | 16.2 * | 27.2 | 50.8 | 19.5 * | 35.2 |
| Unique | 33.2 | 15.5 * | 24.3 | 38.7 | 18.6 * | 28.6 |
| White Moth | - - | 12.9 | 13.0 | 78.2 | 16.6 * | 37.2 |
| Mean | - - | - - | 24.4 | - - | - - | 32.9 |
| LSD (P=0.05) | - - | - - | 3.8 | - - | - - | 3.9 |
1 "*"and "ns" indicate that mean in previous adjacent column is either significant or not significant, respectively, at the 0.05 probability level from mean in column.
Table 3. Average bloom length as affected by pruning and cultivar for irrigated and non-irrigated plantings of Hydrangea cultivars at UKREC, Princeton, KY.
| Cultivar | Pruned | Not Pruned | Mean | Pruned | Not Pruned | Mean |
| Non-Irrigated Planting | Irrigated Planting | |||||
| Average Bloom Length (inches) | ||||||
| Alice | - - | 3.5 | 3.6 | |||
| Annabelle | 3.5 | 3.1 ns1 | 3.3 | |||
| Boskoop | 5.3 | 3.4 * | 4.2 | |||
| Kyushu | 5.0 | 7.2 * | 6.1 | 7.2 | 8.7 * | 8.0 |
| Pee Wee | 5.0 | 4.1 ns | 4.5 | 7.5 | 5.5 * | 6.5 |
| Pink Diamond | 6.8 | 5.0 * | 5.9 | 7.3 | 5.3 * | 6.3 |
| Tardiva | 5.5 | 3.9 | 4.7 | 8.1 | 5.8 * | 6.9 |
| Unique | 5.0 | 3.4 * | 4.2 | 7.7 | 4.6 * | 6.2 |
| White Moth | - - | 5.4 | 5.3 | 7.2 | 5.5 * | 6.0 |
| Mean | - - | - - | 4.7 | - - | - - | 6.7 |
| LSD (P=0.05) | - - | - - | 1.2 | - - | - - | 0.9 |
1 "*"and "ns" indicate that mean in previous adjacent column is either significant or not significant, respectively, at the 0.05 probability level from mean in column.