Q&A Mailbag

By Martha Kirk, Colorado Master Gardener

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If you are looking for answers to gardening questions, look no further. The master gardener help desk receives daily inquiries on a wide range of landscape topics, including lawns, trees, shrubs, vegetables, soil, perennials, and insects, and wants to share them with you. Whether you are new to Colorado or a seasoned gardener, there is always something new and interesting to learn.

Featured Topics in this Issue

  • Fall vegetables
  • Planting trees
  • Weed control

Q. What vegetables can I plant as a second crop?

Fall is a great time to plant a second crop of vegetables. Swiss chard, lettuces, kale, spinach, and peas are a few of the more common choices. These are cold-season crops, so they can survive the first frost that may occur early to mid-October. When deciding what to plant, check the seed packet for “days to maturity” to make sure there is enough time to harvest. Row covers and cold frames can help extend the season.

Q. What trees can I plant this fall that have low-to-medium water requirements?

First, only plant deciduous trees in the fall, not evergreens. Evergreens continuously lose water through their needles and are prone to winter kill.

For larger shade trees, consider Bur Oak, English Oak, White Oak, seedless varieties of Kentucky Coffeetree, Western Catalpa and Western Hackberry. For smaller trees, Crabapple, Japanese Tree Lilac, Bigtooth Maple, Serviceberry and Redbud would make fine additions to the home landscape.

Be sure to winter water once a month or more for newly planted trees. Consult this list for help with selecting trees:

Q. Is fall a good time for weed control?

Yes. Fall is the ideal time to control weeds, especially perennial weeds such as bindweed. Weeds are trying to absorb and store nutrients in their root systems. Herbicides applied at this time are readily absorbed into the root systems. This provides targeted control and helps to weaken the weeds. Quinclorac is especially effective on bindweed. When using an herbicide, you must read and follow the instructions on the label.

Biocontrols are another weed control option. For example, a rust fungus can be applied at the base of Canada thistle and will spread to nearby thistles. Annual weeds, as well as perennial weeds, can be pulled/dug before they go to seed or sprayed with a burn-down product.