Sunday, September 4, 2016

Genetics

Plants, like people, are strongly influenced by their genes to be what they are programmed to be. Here are three examples of plants in my garden that are determined to grow according to their own mysterious dictates.

The sweet autumn clematis (Clematis terniflora) by the new deck was nipped to the ground by rabbits and I despaired. They chopped off all but one stem. But that one stem is carrying on like a hero, and has climbed all by its lonely self up to the railing.


That one stem has produced enough foliage and buds to decorate the railing all the way up and across. It usually blooms in late August, but I am hoping now that it will open those tight buds in time for the garden club's visit next week.


It's late blooming because it got badly trampled in the construction of the new deck in spring, then totally shaded by the compost tumbler when I placed it over the plant thinking it was lost, and then once it finally got going in summer, the rabbits had their evil way with it.


Despite having been stomped, smothered, shaded and decapitated, its roots stored the urgent genetic imperative to grow. It twines and will flower soon with a heady, spicy scent when the tiny starry flowers open. It's fascinating how this plant can carry on with one, and only one, surviving stem and create a complete vision of what the whole vine would have been.

I have two adult ivy plants that I put in along the front walk this spring, and even though they are tiny little plants they are blooming their heads off. These are Hedera helix 'Arborea'.


Adult ivy, also called Poet's Ivy, is the mature version of the long, vining English ivy. When it matures, it changes genetic form, and becomes a flowery, rounded, medium size shrub. You can read what I wrote about it here. Or here. It's a really interesting botanical anomaly.

I have these little plants sited in too much sun, facing south. Ivy wants some shade. I did keep them well watered in this dry summer. They are young, and I'm looking forward to them becoming big rounded, dark leaved forms anchoring the walkway.


Shrub ivy is such an intriguing plant. It actually changes genetically when it matures. A cutting of mature ivy reproduces the genetic instructions to be a shrub, not a vine, with differently shaped leaves. It's truly a different plant. But seed from mature ivy will produce the immature vining form.

The black gum, Nyssa sylvatica, in the front yard is determined to be what its genes are telling it to be. Despite my efforts to keep a strong upright leader growing, this tree wants to be a weeper. It just does.

This is what I noticed yesterday morning when I looked up. The top branches curve over.


This tree has been pruned professionally by Bartlett Tree Experts and I have had at it too to try to get a good top leader, but it's been a struggle.

At first it looked like an upright, pyramidal tupelo tree when it was planted in 2010. Even by 2012, it was still looking upright, much like normal black gum trees. Fall color is always great.


But now, in 2016, it's true identity is showing. It is drooping over and no matter how we prune it, the leader and all the branches cascade downward.


I have noticed in specialty nurseries and catalogs there are several contorted cultivars of Nyssa sylvatica, so apparently it's a tree that is easily bred for twisted branching habits. This one was sold as a normal species form, but it definitely has the genes for weeping.

That would be fine, except it's paired with another black gum in the front yard. The two trees are supposed to be a symmetrical frame for the front of the house. Alas, one weeps, the other is strongly pyramidal and straight.

It is so fascinating to watch the plants in my garden asserting their individual inborn identities.

No comments:

Post a Comment