Hand-pollinating takes dedication
Why would a home gardener want to hybridize her own plants? "The joy of painting with DNA," says Alice Doyle, co-owner of Log House Plants. Less poetic but more to the point, Duncan McGlashan, a British amateur delphinium breeder, says it’s the joy of developing something all your own. "It really is very satisfying thinking what you’ve got is original. That’s the appeal."
Breeding delphiniums takes patience and persistence. Here’s what you need to know to give it a try:
– First a little botany lesson: The delphinium plant reproduces when pollen from the anther (the male reproductive part) is transferred to the stigma (the female reproduction part) and moves down the style to the ovaries, where fertilization takes place and seeds develop. You’ll be able to tell the anther from the stigma because the anthers will be covered with fuzzy yellow pollen. Both occur on the same plant.
– Start with two named varieties (parents) from a nursery and label them.
– Decide which will give pollen and which will receive (mother plant). When plants begin to bloom in June or July, begin stripping anthers off the mother plant (so that it doesn’t pollinate itself). The florets open from the bottom of the stalk up, so work from the bottom up until all florets have opened and you’ve removed all anthers. Don’t get behind on this process because the stigma become receptive early on and you don’t want the plant to pollinate itself. Once the plant starts to bloom, the process of hand-pollinating can take up to three weeks.
– Stigmas are ready to receive pollen when the tubes of the stigma swell slightly like an umbrella and get a little sticky in order to attract the pollen. When you think stigmas are almost ready, pick the florets from the other parent plant (the ones with anthers), put them in a box and move indoors for a day or two to dry. When stigmas are ready, brush pollen from anthers onto the stigmas. Either pull back the petals from around the anther and dab pollen onto the stigma, or use a small brush to transfer pollen.
– It’s a tedious task, but in order to get a pure new variety, you need to pollinate all the florets on a spike. To be sure you’ve pollinated when the stigma is receptive, you can brush on pollen more than once. McGlashan usually does it three to four times.
– If you’re working with more than one pair of parents, wash your hands before you move to a different plant or you may mix pollen and your cross won’t be pure.
– It takes about three weeks to get ripe seed. Once seed is ripe, collect it and germinate right away or store in refrigerator in paper or glassine bags inside a closed jar. When ready to germinate, put jar of seed in freezer for five days. Then sprinkle into sterile planting mix and cover lightly. Put container into a bigger container that holds water so moisture can wick up. Spray top of soil with water. Keep in dark and they should germinate in about 10 days. Once they come up, move into the light.
– The next year when your new plants bloom, choose the one you like the best. Cross that with a named plant that has the characteristic you want. Sooner or later, you’re sure to get something wonderful.