Southwest Yard and Garden

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

spittlebugsSpittlebugs are hiding inside white clumps of cottony foam on this autumn sage plant in Los Lunas. Photo credit M. Thompson.

Question: What are these pea-sized globs of white foam all over the stems of my rosemary plant? Should I be concerned?

Leslie H., Belen, NM

wooly apple aphid flocculence de baca county aspen achenWhite masses found on the edges of old pruning cuts on this apple tree may be evidence of woolly apple aphid populations. (Photo credit A. Achen)

Question: What is causing this white webbing that looks like it’s oozing from old pruning cuts in apple trees?

Question: How much should I be watering my trees? 

-  Multiple Gardeners from All Over NM

Answer (Part 2):

In last week’s column, we learned about how the type of soil in your garden affects tree water requirements. Now we will focus on other considerations, such as rates of water movement, tree species, age, canopy size, and seasonal fluctuations in water needs.

Plants take water up from the soil through their roots all the way to the leaves where it is released into the air. Transpiration is the process by which a plant loses water, primarily through pores in the leaves called stomata. This is a necessary process that involves the use of about 90% of the water that enters the plant through the roots. The other 10% of the water is used in chemical reactions, like photosynthesis, and in plant tissues. Transpiration is necessary for mineral transport from the soil to the plant tissues, for the cooling of the plant through evaporation, for moving sugars and plant chemicals, and for the maintenance of turgor pressure. The amount of water lost from the plant depends on several environmental factors such as temperature, humidity, and wind or air movement.

img 0720 2Cottonwood leaf near Hillsboro, NM in September 2017. Although native to our region, cottonwood trees are no longer recommended for most of our ornamental landscapes because of their high water needs. Photo credit M. Thompson.

swyg1Peach tree stem infested with aphids is likely going to defoliate completely, but this early in the growing season there’s a good chance it will bounce back and be covered in new leaves in no time. Photo credits M. Thompson.

Question: What’s causing our peach tree leaves to wither and curl up completely and should we also be worried about our apricot trees nearby?

Lorraine J., Los Lunas, NM

Late April to early May is usually a safe time to move houseplants outside in most of New Mexico, but transition carefully and watch the forecast!

frost damage on houseplants wikicommonsThis aloe plant was frostbitten so badly it might not make it. Image from Dezidor, Wikimedia Commons.

Reprint from April 2011. Written by Dr. Curtis Smith, retired NMSU Extension Horticulture Specialist, with additions by Dr. Marisa Thompson. 

Question: Is it safe to put houseplants outside now? After I moved my plants outside last year most of the leaves died.

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.