2010 Summer – From the Archives

One of the worst things about growing specialty cuts is the short availability season for many of our crops. It seems to me that just about the time my customers remember what the product looks like and become familiar with how to use it, the bloom is finished for another year. Different regions tend to produce blooms at different times, and this helps build a more constant supply for our customers. Still, the short bloom period is a difficult marketing barrier. For a new flower to become more widely used, a longer availability is necessary. It would be nice to find a happy medium: from two weeks’ availability to always being available like our boring competition (roses, mums and carnations)!

Lysimachia clethroides is an excellent cut flower. It is a prolific bloomer very usable in bouquets, vase work, and floral arrangements using Oasis. This flower reacts very favorably to a postharvest treatment with silver. We use Rogard sustaining solution with Regard RS, and the blooms practically grow in the vase. I have seen arrangements with a 3-week vase life! If properly cooled and conditioned, this flower ships very well. Its straight shape packs well, yet loosens up when removed from the shipping sleeves enough to be flexible in arrangements.

The common names “gooseneck loosestrife” and “goose goes walking” describe the charm of this flower in arrangements. It is fluid and moves, adds hard-to-find white, and lasts.

Lysimachia could replace overused flowers like gypsophila and ‘Monte Casino’ asters, if the bloom period could be extended.

The flowering stems range from 16-48″ with white flower racemes between 1″ to 6″ long. The range is dependent upon how old the plant is, how it is grown, and how it is pinched. This flower must be netted to get straight stems. Lysimachia is very prone to iron chlorosis. It is a heavy feeder. We have found that a very heavy spring application of hot cow manure (2 inches) will eliminate most of the chlorosis and produce the rich blue-green foliage that too much nitrogen often produces. In most plants this would invite serious aphid or white fly infestations, but lysimachia seems to be immune to these pests.

The problem with lysimachia is that if it is grown as a perennial in a garden bed, the plant will flush heavily for two weeks, and be done for the season. Furthermore, the first year the bloom will be moderate, the second year very heavy with nice stem length and girth, and the third year a decline will set in, with flower size and stem girth decreasing. The fourth season undivided is not usually marketable.

How do you tame this wild beast? The goal is get a profitable cut with an extended bloom period, producing a good stem length with a nice-sized flower. In conversations with other growers, and from my own experiences, several things become clear.
Lysimachia must be constantly lifted and divided. I now divide all beds after the second year. The second-year plants produce the best blooms and stem size. First-year plants give some bloom, usually 3 to 4 weeks later than the second year plants. In addition, fall-planted divisions bloom earlier than spring-planted divisions. The bloom can be further extended by holding some divisions in cold storage (28F), and planting out 4-6 weeks later. This combination will extend a two-week flowering period to over two months.

The only limitation to forcing lysimachia seems to be daylength. The shorter days of fall in Oregon begin to cause extensions of the green flower bracts and a flattening of the flower spike. I have observed the same flattening in late-blooming veronicas. It’s my bet that this problem could be corrected in a cold frame or greenhouse with carnation-type daylength lighting (60-watt incandescents, 6′ on center placed above the planting beds and set to extend daylength to 12 hours). I would love to hear from anyone with experience doing this. Maybe this would be a great research project for the ASCFG Research Foundation. Donations, anyone?

After conversations with Gerard Smit of Smit Greenhouses, in the Vancouver, BC, area, I have experimented with sequential pinching to stagger the bloom within a specific planting. In our first attempt at pinching we cut half of a planting back to 6″ when all the plants had reached about 18″. This retarded the bloom of the pinched section by 4 weeks, but produced twice as many stems which had smaller flowers and thinner stem diameter. The product was marketable because no other lysimachia was on the market.

A preferred approach is to wait until the beds have grown 6″ or higher, and to cut sections back to the ground every two weeks. The resulting regrowth is not so spindly and flower size is larger. The trick here is not to pinch back so late as to retard the bloom into the short days when you no longer get a good bloom. This will vary by area and must be learned through personal experimentation.