Posts

Showing posts from 2018

Saving Zinnia Seeds

Image
Southwest Yard & Garden by Dr. Marisa Thompson
Question: I have a large monarch butterfly garden, and I gathered zinnia seed heads to plant next spring. Zinnia seeds appear to have two distinct morphologies. The ray flower seed is shield-shaped and the disk flower seed is smaller and flatter. Which of the seeds is viable? I have researched and found some who say only the ray seed, some say only the disk seed, and some say both. Please let me know which zinnia seed is most viable and why. -Tim P., New Mexico
Answer: I know exactly what you mean. I’ve had this question before myself. Zinnias were one of my first garden successes when I moved to Las Cruces in 2009. I too gathered the seed heads and I too wondered which part was the true seed that should be saved. That year I just saved the whole shebang. In the late spring I crunched up the entire dried flowers and sprinkled them around the garden. It worked, so I kept that routine right up to today. Our office building at the NMSU Agri…

Mistletoe: The Kiss of Death (not really! but we should still try to control the spread)

Image
Southwest Yard & Garden by Dr. Marisa Thompson
Question: What trees are resistant to mistletoe? -John Allen, NMSU Extension Agriculture Agent & Program Director, Socorro County Answer: OK, no one really calls mistletoe “the kiss of death” as I did in this week’s column title. That’s my attempt to grab readers by the eyeballs. Mistletoes don’t tend to kill their tree hosts, but it is possible, and they certainly can do harm, leaving the host plants more vulnerable to other stressors. The genus name for true mistletoe is Phoradendron, which means “tree thief.”
Mistletoe is usually green or at least a puke-green color. Winter is a good time to detect it in deciduous trees because the tree leaves have dropped and the mistletoe is temporarily exposed. Greenness is a clue that mistletoe contains chlorophyll and can photosynthesize on its own, so it’s not necessarily stealing sugars from the host plant. It’s still a parasite because it lacks normal root tissues. Instead of roots, mistlet…

Poinsettias can be “New Mexico True” TOO!

Image
Southwest Yard & Garden by Dr. Marisa Thompson
Question: I love the poinsettias I bought this year, but one is already starting to droop pretty badly. How do I keep them looking good through the season? -Elizabeth S., Santa Fe
Answer:
Did you know you can purchase locally-grown poinsettias at plant nurseries across the state? I interviewed poinsettia growers in Albuquerque, Santa Fe, Las Cruces, Radium Springs, and Estancia to find out more about poinsettia production in New Mexico, how to get my hands on one (or a few) this season, and how to take care of them at home. The City of Albuquerque Parks and Recreation Department grows its own poinsettias for holiday displays at the Albuquerque International Sunport and various City Hall buildings. I remember being struck by the vibrancy of the gorgeous Sunport poinsettia planters last December. This year, I got to visit the city’s greenhouses twice to check on the growing process. When I first visited in late August, each plant was looking …

Cochineal Scale on Cholla and Prickly Pear

Image
Southwest Yard & Garden by Dr. Marisa Thompson

Question: What’s the white cottony stuff growing on my cholla cactus? And should I do anything about it?
-Albuquerque resident via Bernalillo County Extension Horticulture Agent, Sara Moran Answer: Although it looks like cotton fibers, that stuff is actually a fine wax produced by adult cochineal scale insects, and little black specks may be their nymphs. It’s common around these parts on cholla (Cylindropuntia spp.) and prickly pear (Opuntia spp.) cacti. The similar-looking white beards on other cacti, like the Peruvian old man (Espostoa lanata) and Peruvian old lady (Espostoa melanostele), are normal, healthy modified tissues, not an insect product. The white waxy coating made by cochineal scale on landscape chollas and prickly pears helps protect these true bugs from predators—and insecticides. I’ve seen prickly pear pads almost completely covered in that white fluff. It’s more common to find mild infestations, like the ones Doña Ana C…

Deciding Factors for Deciduous Color: All the Leaves are Brown, and the Sky is Turquoise

Image
Southwest Yard & Garden by Dr. Marisa Thompson Question: Why are some cottonwood trees turning brown rather than yellow this fall? Sometimes a portion of the tree (often the lower portion) turns brown while the crown does turn yellow. I think I have seen this in other years, but this fall it seems more pronounced. Is it weather related? Moisture?
-Wes B., Albuquerque, NM
Answer: Explanations for why leaves change color the way they do can be related to the species or cultivar, temperature fluctuations, seasonal day length changes, and potentially the soil moisture levels too. A general rule is that while temperature tends to affect the intensity of leaf color, it’s the shorter days and longer nights that trigger overall color change. Chlorophyll is the green pigment that starts the process of photosynthesis by helping convert sunlight, carbon dioxide, and water into sugars that travel through the plant to other branches or roots where the plant uses them as food. Normally, chlorophyll…

Fertilizer Pros and Woes

Image
Southwest Yard & Garden by Dr. Marisa Thompson Question: I’ve seen conflicting advice online on whether or not to fertilize trees now to promote healthy root growth.

-Camille R., Albuquerque
Answer:Don’t fertilize anything in fall because we want growth to slow with dormancy, and the salts in fertilizer will either just sit there and be unhealthy for soil/roots or actively damage roots. When carefully selected and applied, fertilizers can help boost a plant that’s already putting on a flush of top growth, like in the spring and early summer. In our areas, applying fertilizer now may extend late-season growth, and that new tender growth is particularly susceptible to cold injury. Water, applied low and slow to the whole root zone, is the best “fertilizer” to help trees through the winter, plus a cozy, fibrous mulch layer on top of the soil. Depending on how warm this winter is in your region, how much snow we get (fingers crossed!), your soil type, the tree species, and the age of the…

Lilac It or Not: Hold Off On Pruning Until Flowers Fade

Image
Southwest Yard & Garden by Dr. Marisa Thompson Question: I've got some spindly lilac bushes. Should I cut them back now or wait for spring? How can I make them grow fuller? -Lisa W., Santa Fe Answer: Good news—you can wait even longer. For maximum flowering effect, keep your clippers in their scabbard until after the lilac flowers have senesced (faded). Lilac bushes bear flowers on last year’s growth, so if you prune in the late summer or fall when branch growth slows in preparation for dormancy, you’ll likely diminish—or extinguish—spring blooming. This is also true for other early spring bloomers, like forsythia and cherry trees. In last week’s column, we learned about the bearing habits of fruit trees and how stressful environmental events, like drought or typhoons, can trigger plants to flower at the wrong time. A friend from Wilmington, North Carolina told me this past weekend that many of the area’s dogwoods, redbuds, Bradford pears, and azaleas are blooming out of sync, and…