Weigela

What’s blooming in the area: Catalpa, Russian olive, tamarix, Austrian copper and double pink shrub roses, Apache plume, yellow potentilla, silver lace vine, narrow-leaved yucca, red hot poker, peony, tumble mustard, hollyhock, fern-leaf globemallow, oxalis, white evening primrose, scarlet beeblossom, nits and lice, bindweed, datura, purple locust, alfalfa, Dutch and yellow sweet clovers, purple loco, sweet pea, purple salvia, native dandelion, goat’s beard, hawkweed; June, brome, needle, rice, and three-awn grasses; buds on milkweed and stickleaf; lamb’s quarter up; needle grass seeds letting go.

In my yard looking north: Spirea, iris, golden spur columbine, Harweig evening primrose, chocolate flower, blanket flower, coreopsis, perky Sue, Moonshine yarrow; buds on daylily and anthemis.

Looking east: Dr. Huey and Persian yellow roses, winecup, oriental poppy, coral bells, Jupiter’s beard, snow-in-summer, Bath’s pink, sea pink, pied snapdragon, Maltese cross, pink salvia, pink evening primrose; buds on raspberry and coral beardtongue; pods on Siberian pea.

Looking south: Miniature rose, beauty bush; bundle weed and zinnia seeds planted last Sunday up.

Looking west: Rumanian sage, catmint, baptista, blue flax, vinca, chive; buds on sea lavender; perennial four o’clock up.

Bedding plants: Zonal geraniums.

Inside: Aptenia.

Animal sightings: Jack rabbit in arroyo, hummingbird, gecko, cabbage butterfly, bees on catmint, baby grasshoppers, large black harvester and small red ants, mosquitoes, flies; hear crickets.

Weather: Smelled Jemez fire Tuesday night; temperatures getting into 90's in afternoons; last attempted rain 05/28/09; 14:31 hours of daylight today.

Weekly update: This is the time we should be looking at our roses and watching vegetables germinate. Instead, everyone’s complaining the iris didn’t bloom and wondering when they should have put out their tomatoes.

Shrubs have had a particularly trying year: winter cold killed branches on any that were weak or tender, but icy moisture encouraged the roots of some to put out new growth. The reasons depend on the plant: buddleias are herbaceous in much of the country, but the spirea that died back has never done well.

My weigela’s problems are both genetic and historic. I planted something called "pink flowering" in 1997 that never did as well as the nearby beauty bush. The leaves were killed by cold in late April of 2000 and the wind battered and wilted them in May of 2003.

Then the grasshoppers hit the summer of 2005 and not only ate the leaves, but apparently any latent growth that had formed. The next spring, lots of stems were still alive but had no leaves. New leaves did finally come up from the base. It's limped along since with a few stems surrounding a clump of pealing, dead wood I never had time to prune out. Last year the flowers were pale, almost white.

Now, this year, no flowers, and after a month, there are leaves on only four stems. However, last weekend there was lots of new growth at the crown.

The caper family member should do better here. Weigela florida grows from Inner Mongolia through northeastern China into Korea. However, a group at Iowa State found plants grown from tissue culture were more like to produce branches than those grown from cuttings which tended to let the primary stems dominate.

Sydney Waxman found the length of day light was also important in producing good shrubs from cuttings. If the weigela stock was growing in long day conditions, it produced more roots if the cutting was also grown in long days.

That may sound somewhat self-evident but it means nurseries producing commercial plants can only make cuttings at certain times of the year, and those times may not coincide with their production schedules. Since I bought my plant at the local hardware, I assume the least expensive, most conventional propagation methods were used, and the plant I got was inherently weak.

At the time Waxman was doing his research at Cornell, the Nitsches in France determined weigela’s sensitivity to daylight was located in the youngest leaves. Normally, when days grow shorter, the shrub begins to prepare for winter. However, if the leaves are removed the plant ignores day length and continues producing new growth.

That year the grasshoppers attacked, they fooled by plant into continuing growing into the fall, making it even more vulnerable to winter injury than usual.

Last year’s conditions were much like this year: a short period between chilly morning temperatures and a hot June, with an early drought. Last year the monsoons failed to maintain normal plant health and the winter had colder, wetter stretches than usual. Last year’s new growth, which would produce this year’s flowers, probably didn’t develop or died, and the older, grey stems are having problems producing leaves.

But, now that the days are longer, those scarce first leaves are able to send messages to the plant’s nerve center, and new vegetative growth is appearing. I may not get to see any pink funnels this year, but I am, once again, able to watch nature adapt to unexpected problems with biological mechanisms developed for another world.

Notes:
Ghrist, Angela C., Loren C. Stephens, and Jack L. Weigle. "Growth Habit of Weigela florida as Affected by Stock Plant Propagation History," Journal of Environmental Horticulture 9:123-127:1991.

Nitsch, J. P. and Colette Nitsch. "Photoperiodic Effects in Woody Plants: Evidence for the Interplay of Growth-Regulating Substances," Conference on Photoperiodism, 1957, proceedings published as Photoperiodism and Related Phenomena in Plants and Animals.
Waxman, S. The Development of Woody Plants as Affected by Photo-Periodic Treatments, 1957, described by Nitsch and Nitsch.

Photograph: Weigela coming up from roots, 31 May 2010.