Southwest Yard and Garden

This column comes through the Grant County Extension Service out of New Mexico State University.

jujube tasting workshop sept 2017 shengrui yaoJujube fruit from different cultivars on display for the annual Jujube Tasting Workshop held in Alcalde each September. Some cultivars are sweeter and others are tangier. Photo credit S. Yao.

Question: What fruit trees are recommended for my area?

Karena, Dulce, NM

jeroens plum and peach in clovis 2019 copyPlum buds (left) are in “bud burst” and “first white” stages of floral development. Thirty minutes of exposure to temperatures in the mid-20s are expected to kill 10% of buds in these stages, and temperatures in the low 20s might kill as much as 90% of the flower buds. Peach buds (right) in this “first pink” stage are slightly more resilient than plum buds. Temperatures in the mid-20s are still expected to kill 10% of the buds, but in order to kill 90% temperatures would have to drop into the mid-teens. Photo credit J. van der Ploeg.

img 0442 2Pomegranates can create beautiful color when leaves turn bright yellow in fall. In this October photo taken at the NMSU Los Lunas Agricultural Science Center, ‘Afganski’ cultivar pomegranates are the foreground and tall ‘Encore’ peaches with dark orange leaves are in the back. Photo credit M Thompson.

Question: When should I prune my pomegranate tree and how much wood should be removed during pruning?

 - Extension Master Gardener Trainees in Valencia and Bernalillo Counties

By guest contributor Dr. Gill Giese

powdery mildew evident on leaf top surface. giese copyPowdery mildew evident on leaf top surface is easier to see when leaf is turned “sideways” to catch light on infection sites that are in sporulation. Photo credit G. Giese.

Question: My husband and I are planting a few Marquette grape vines this year in Santa Fe. I would like to plant a tree approximately 8 feet from the vines. Could you recommend some trees that would be “a good idea” to plant close by? I read that planting a rose bush at the vines will help to indicate any diseases since the roses would get this first. Is this a good thing to do? Are rabbits a problem with grape vines? We have quite a few roaming freely. Should we protect the vines with a net around them?

with guest contributors Dr. Carol Sutherland and Dr. John Formby

pinon1Black specks on these older, browned piñon needles at a park in Albuquerque back in in March 2018 are a sign of a piñon needle scale infection. (Photo by M. Thompson.)

Question: I took these photos on one of the piñon trees nearest our house. We have thousands of piñon here on our land and our neighbor’s land, some of which have died within 12–14 days of turning brown. We would hate to see an epidemic, but it does seem to be spreading. What is it and what should we do?

- Paula P., Mora, NM (submitted via NMSU Extension Agent for Mora County, Suzanne DeVos-Cole)

silverleaf nightshade flower w 15Silverleaf nightshade flowers are beautiful, but these weeds are invasive and parts of the plant are toxic to humans and animals. Photo from NMSU Extension Guide “Silverleaf Nightshade” W-15.

By guest contributor Dr. Leslie Beck 

Question: Silverleaf nightshade and nutsedge are taking over parts of my yard! Please help. Organic control options are appreciated.

Helen B., Las Cruces, NM 

cenchrus sandburs and stalk photo from weeds.nmsu.edu 2

goatheads puncturevine photo from weeds.nmsu.edu

Both are annual weeds with vengeful, spiny seeds, but sandbur (top) is a grass and goatheads (bottom) are a flowering, broadleaf species. Photos from the NMSU website here.

Question: Can you help me battle my weeds organically? I’ve got sandspurs and goatheads. Are there soil conditions weeds hate?

Helen B., Las Cruces, NM 

Answer: Ouchie, that’s a nasty duo of weedy enemies. Most readers can commiserate all too well. Sandbur is a grass of the Cenchrus genus, also commonly referred to as “stickers” or “sandspurs.” Goatheads (Tribulus terrestris), also known as “puncturevine,” have tiny yellow flowers; delicate, compound leaves; and spiny seeds that are even meaner and tougher than sandburs. Many people mistakenly call sandburs “goatheads,” and I understand why. Both have spiny seeds. Both get all tangled in your socks and shoelaces when you’re not looking. Here’s the quickest way to tell the difference: place one of each seed type on the floor and then step on them both while barefoot. They both hurt, but pay attention to the depth of the pain and the length of time that pain persists. The goathead spines feel like they punctured all the way up to your knee and the spot of contact may ache for over an hour. You’re welcome.

Question: The Texas red oak, live oak, and pecan trees in my yard were looking bad going into the fall, as were my neighbor’s honey locust and maple. When I searched for problems online, I found different possible pests and diseases for each tree. Can you help me narrow down the possibilities?

Richard V., Hobbs, NM

Answer: This is Part II of the column on diagnosing tree problems. Last week, we learned that water stress and weed whacker injury are the most common tree problems in our landscapes, and that the rooting area necessary for large trees to survive and grow is much bigger than most folks realize.

southwestjanRed arrow is pointing to a porcupine munching on tree bark way up in the canopy of a cottonwood at the Albuquerque Botanical Garden in February 2018. (Photo credit M. Thompson)We also touched on the reasons why symptoms are rarely sufficient for conclusive diagnosis of a tree disorder. This is partly because symptoms may point to secondary or tertiary problems. Many—but not all—insect pests and pathogens are more likely to attack trees that are already stressed.

Plant stressors can be broadly divided into two categories: biotic and abiotic. Biotic stressors are caused by living or once-living organisms, like insects, bacterial and fungal pathogens, and animal pests.

Nature's Notebook is a national, online program with the USA National Phenology Network that uses amateur and professional naturalists to record plant and animal observations in a given location over time. The steps for becoming a volunteer are straightforward. And you can set your backyard as a location or pick a public space and get a group to sign up together (Visit Nature's Notebook here).