September 24, 2016

1 - The fact that rains may come in different seasons gives Southwestern native landscapes and xeriscapes a variability in which plants prosper and dominate from year to year.

Yard and Garden September 24, 2016

Q.

I have been concerned since spring that my yard has almost no annual NM sunflowers. We have lived in this spot for 25 years or so, and always have an abundant number of these volunteers spring up. I encourage them because they are beautiful, and provide winter food for the finches that visit. Last fall, many of them failed to bloom, with their flower heads falling over just prior to their opening. This lack of bloom last year, probably resulted from less seed to sprout this year, but what caused last fall's flowers to do this? My hope is this is not related to that salt cedar beetle that was imported to defoliate the salt cedars, but the timing is suspect. Has anyone looked into what is going on? Every late summer our roads and ditches are lined with these plants, and I see almost none.

I normally rely on them to provide food for our winter birds, but it looks like I will be buying bird feeders and seed for my guests this year.

- Nancy E.

Valencia County

A.

In a separate communication, Nancy sent pictures of some weevils she collected from her sunflowers this year. I suggested that she send samples to Dr. Sutherland, NMSU Extension Entomology Specialist, for identification. She has sent information to Dr. Sutherland and we are waiting. However, I think these are seed weevils and may not have been involved in the failure of the flowers to open last year. That may prove to be a bad assumption. However, in the case of native plants, the chances of dormant seed persisting in the soil from previous years increases the chances of plants growing even after a year with few flowers.

I am considering environmental factors related to this year's precipitation patterns as a reason there are relatively few sunflower plants. I also noticed many fewer native sunflowers in my garden this year. I have a few, but they are smaller than usual. I have attributed this condition to the timing of rainfall. I had noticed this previously along the roadsides - some years produced many and large sunflowers, other years few to none, and smaller. Timing of precipitation seems to be related to this. I have observed this with other wildflowers as I have driven across the state. Some years the grasslands exhibited few wild flowers, and then some years there was a great display of wild flowers in the previously, apparently, only grassy grassland.

This year was quite dry through most of the spring and into the summer. Late winter is when sunflower seeds would have germinated. Some will germinate later. According to CoCoRHaS Data, March was extremely dry and would not have supported the germination of the sunflowers. April and May had more moisture, but not much and poorly distributed precipitation. Seed may have received enough moisture to germinate, but not enough to sustain them and the seedlings may have died.

In my garden, the Jerusalem artichokes (a sunflower plant) and Maximilian sunflowers are blooming now. The Jerusalem artichokes were in the garden received drip irrigation (they wilted often), and now they are fairly tall and flowering. The Maximilian sunflowers were irrigated some, but I was traveling a lot this summer so they did not get as much water as usual, so they are short, but blooming. These are both perennial plants, as opposed to the annual sunflowers, so the dry spring was less able to prevent them from growing (and helped by the fact that I irrigated them). The birds will be visiting these plants from now through the winter.

I am not positive that the cause of the lack of sunflowers was precipitation patterns affected sunflower populations, but I suspect that this may provide a part of the answer. This impact of varying seasons of precipitation gives Southwestern gardeners the chance through strategic planting and plant selection to have landscapes that appear different from year to year. With proper choice of plants that respond to winter rains, spring rains, and summer rains they can have plants that prosper one year and different plants that dominate the landscape in other years. Those that do not prosper in some years will often survive as smaller perennial plants or as dormant seeds, so the garden is not lost, rather it is naturally altered from year to year.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

Links:

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!