Dial-a-Garden Message

for the Week of Monday, August 24, 2009

Susan Rose, Horticulture Education Specialist
Colorado State University Extension Tri River Area

Thank you for calling Dial-a-Garden. This message was recorded on Tuesday, August 25, 2009.

The evapotranspiration rate for the week is 1.6 inches. The rain has been heavy in spots but it hasn’t been consistent - as always, check your soil to see if it needs watering.

Silver maples and other trees are suffering badly this year from chlorosis, or the premature yellowing of leaves. In some cases, the trees never greened up properly in the spring and have been yellow all year. Although this problem is commonly referred to as an iron deficiency, in our soils it is more likely to involve insufficient nitrogen. Several factors may be involved when trees are chlorotic. If our soils stay cold into the spring, as they did again this year, a tree may not be able to take up the nitrogen it needs at that time which can result in a lack of green leaves. Watering is also a factor in many cases; excess water flushes nitrogen out of the soil. Trees with plastic over their roots are frequently chlorotic from a lack of oxygen and excess moisture in the soil. Shallow-rooted trees, such as the silver maples, need to be watered monthly over the winter to keep their roots alive and healthy. See our publication on winter watering at www.coopext.colostate.edu/TRA/PLANTS/wntrwtr.html or give the Master Gardeners a call at 244-1836. Do not fertilize at this time; the trees need to be hardening off for winter. Apply a nitrogen fertilizer in the spring when the leaves emerge, at the rate of one pound of actual nitrogen per thousand square feet.

It is not unusual for trees that have been planted in the last year or two to have dry, burnt edges on their leaves late in the year. The condition, called leaf scorch, is an indication that the tree has not yet established a strong root system. Encourage the growth of new roots by watering deeply but then allowing the soil around the tree to dry out somewhat before watering again. You don’t want to let the soil become completely dry, but roots need oxygen in order to grow and there is no oxygen available when the soil is kept too wet. More information on leaf scorch is available at www.westernslopetrees.org or give us a call at 244-1836.

Late August or early September is a good time to seed a new lawn. The key to success is properly prepared soil. A fairly coarse organic material such as wood chips or bark mulch should be worked into clay soil as deeply as possible. Ideally, when amending the soil we would add three to six inches of this organic material, but many of us don’t have the equipment for incorporating this much material at one time. We will need to add an inch or so and work that in, and then repeat the process. Our goal with a lawn is to prepare the soil only one time; it’s a lot of work but worth the effort to do it right. Lawn problems related to poor soils are much harder to correct after the fact. Since salts in the soil are such a problem in our area, begin with a salt test; bring in about a cup of dry soil to your local Extension office and let us have a look. There is no charge. Some types of turfgrass are better able to tolerate salts in the soil than others, and the Master Gardeners will be able to advise you. Check out our demonstration turf plots at the Arboretum on the Mesa County fairgrounds.

The gardens at the Mesa County Arboretum are putting on a great late-summer show. Our gardens are open all the time, and there is no charge to come take a look around. If you have any questions, stop in between 8:00 a.m. and 5:00 p.m., Monday through Friday and we’ll do our best to help.

Give the Master Gardeners a call with your yard and garden questions, or bring in a plant sample if you are having a problem with it or want identification. We’re located on the Mesa County fairgrounds at 2775 Highway 50, and our number is 244-1836. In Delta, we’re at 525 Dodge Street, across from the courthouse; the number there is 874-2195. In Montrose, you’ll find us at 1001 N. Second Street, in Friendship Hall, and the number there is 249-3935.

Thank you for calling Dial-a-Garden. This message will be updated next week; have a great week!

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