What a difference a year can make. Perennials usually get bigger and better! Nine of the ten perennials tested for cut flower production increased in stem yield and stem length compared to 2016. In the second year the average stem length for all species was longer than 12 inches, but the longest stems (those over 20 inches) were obtained from Agastache ‘Blue Fortune’, Monarda ‘Jacob Cline’, Perovskia ‘Longin’ and Rudbeckia ‘Viette’s Little Suzy’. All four were also quite productive in both number of stems per plant, and winter hardiness, as 94-100% of the plants survived to the second season. Helenium ‘Ruby Tuesday’, Leucanthemum ‘Goldfinch’, Leucanthemum ‘Real Glory’, and Monarda ‘Cranberry Lace’ were not included in this article because the average stem length was less than 12 inches.
Agastache ‘Blue Fortune’ is easy and pleasing to harvest with its long, sturdy stems and fragrance. It also fits well into small places in arrangements or provides height. The lighter color blends well with many other flowers compared to the bright purple of Agastache ‘Blue Boa’.
Monarda ‘Jacob Cline’ is one of our favorites, because it is a great producer and it can be used in three different ways. First, stems can be harvested before flowers develop making the burgundy sepals the main focal point (Fig 1A). Second, if harvested just before full bloom, the bright red flowers look like fireworks against the burgundy sepals. Finally, you might be able to harvest the older seed heads (Fig 1B).
An honorable mention is Veronica ‘Charlotte’. The variegated foliage on this plant is a bonus and the second year performance was worth the wait. The first harvest of the season produced the longest stems. The spike flower works great with Veronica ‘Tranquility’ and other pink flowers like Delphinium ‘Planet Pink’ from this year’s seed trial (Fig. 2).
The Details: Rooted liners were received from Ball Horticultural Company during spring 2015. Three blocks of 12-16 plants were planted, and cut stems harvested during the 2016 and 2017 seasons. Production data consisted of the number of stems produced that were equal or longer than 12 inches, and the length of the first 100 stems (≥12 inches) harvested from each block. Stems were processed for postharvest vase life tests by recutting all stems to a similar length. The following treatments were used for our postharvest trial:
1) Hydrator only (4 hours)1) Hydrator only (4 hours)
2) Holding preservative only (2 days)
3) Hydrator for 4 hours followed by holding preservative for 2 days
4) Tap water only (as a control)
Floralife Hydraflor 100 was used as the hydrator at 1.0 ounce per gallon, and Floralife Professional was used as the holding preservative at 1.3 ounces per gallon (the rates listed on the packaging). After treatment, stems were placed in tap water and held at 68 ± 2oF under approximately 200 foot-candles of light for 12 hours per day. The vase life for each stem was recorded. Termination point was typically when 50% of the flower(s) or florets on the stem were brown, wilted, drooped over, etc. This study helps us provide accurate information on how long these flowers will last, and how to increase vase life. These perennials will be held over one more winter to get a better handle on their hardiness in North Carolina.
Don’t be afraid to give perennials a try. They can be a great supplement to your annual crops, providing some interesting colors and habits while reducing preparation included in buying seed, nurturing seedlings, planting, and tilling fields. For more information on our postharvest trials or production research check out past articles in The Cut Flower Quarterly, or go to our website: https://cutflowers.ces.ncsu.edu/.