In many articles I have described plants as long-term, short-day and neutral. Is this an indication of the number of hours of sunshine? How do plants respond to changes in day length?
Day length or irradiation is the main reason plants are used in different processes. Plants use day length to tell them when to go dormant in the fall and when to wake up in the spring.
Most of us assume that climate change will bring peace. But temperature changes are not constant and are not always sensitive enough to protect plants from autumn temperature extremes. Similarly, an unusually warm winter can stimulate new growth that will be damaged when cold weather returns to normal. I noticed that the trees that grow here shed their leaves at the same time as similar tree species in winter climates.
The formation of flowers and the subsequent development of fruits and seeds are other important developmental processes that depend on the length of the day. Most of the spring and summer flowers we grow in our garden are perennials. They don't all grow at the same time. Each species begins flowering at a specific day length and continues to flower several times until a shorter day length is reached again.
Autumn plants such as chrysanthemums are short day plants and begin to bloom when the day length is short. Greenhouse growers use dark or light fabrics for tulips at any time of the year.
Breeding date-neutral strawberry cultivars for growing strawberries in California is an interesting story. Royce Bringhurst, a professor of plant breeding at the University of California, Davis, studied wild strawberries that grow in the mountains of Utah and bear fruit throughout the summer. This shows their everyday neutrality. Until recently, all horticultural and commercial strawberries were perennial crops, bearing fruit for a maximum of six weeks in late June and July.
Bringhurst crossed wild Utah plants with commercial problems, selecting them for their size and commercial character, as well as their everyday neutrality. This species bears fruit all season along the coast of California. Produces winter through fall in Washington and Oregon. The UC strawberry variety sold locally is called Seascape.
Most perennials are long-day plants with a limited flowering season. However, there are some perennial plants that are naturally diurnal and have a longer flowering period. My three favorites are Roseanne geranium, Monbeam Corpopsis and Peruvian lily (Alstroemeria).
Green Fuse botanists have a breeding program to develop independent daylilies to extend their flowering time.
One of the original varieties, the Shasta Daisy Carpet Angel groundcover is one of America's top picks.
Green Fuse does not sell directly to farmers, only to greenhouse growers and in turn to retailers. These new independent day constants are called First Light. I look forward to seeing some of these in full-service grocery stores and garden stores.
