When to prune juniper trees - Creeping sorrel lawn weed

Question:

When is a good time to prune lower branches of a juniper tree? And when do I prune back a bush honeysuckle?

Dena B.
Eastern N.M.

Answer:

The best time to prune junipers is late winter and early spring just before growth begins. However, because junipers are usually very vigorous, they can be pruned almost any time. You can prune them now with little harmful effect on the tree.

The bush honeysuckle should be pruned during the dormant season if you will remove many branches. It grows here, but prefers a cooler environment, so take care when pruning to avoid adding stress to the existing heat and drought stress. Since this is a plant that forms its flower buds in the late summer, winter pruning will remove some of the next year's flowers and fruit. If you are only removing a few smaller branches, you can even prune this shrub now. Pruning now will prevent the removal of preformed flowers and result in more flowers next year compared to winter pruning. The important factor is how much you will prune away and how well you irrigate to reduce the environmental stress on the shrub.

Question:

We live in Rio Communities, and last year we started having problems with a type of clover trying to take over our lawn. This clover is purplish in color, and grows very fast, and kills the grass. We have tried various weed killers without any success. We have lost about a sixth of our lawn to this plant, and do not know what to do. We have also chopped, and pulled it out, and it still comes back. We do not want to lose the rest of the lawn. What do you suggest?

Janice & Jorge M.

Answer:

Your problem is probably not actually a clover, rather it is a plant called creeping woodsorrel. It has leaves like clover, but the flower is very different. This is a difficult weed to control.

As you work to manage this weed, always mow the infested part of the lawn last and then, before moving the mower away from the infested area, wash seeds and plant parts from the mower. This will help prevent the spread of this weed to other parts of your lawn. Digging the plant can be effective if you dig deeply enough and if you also remove the side plants that form as runners from the parent plant form roots where they touch the soil. If you leave small plants when digging, they will grow and renew the problem. Frequent digging of newly sprouted plants is helpful, or a preemergent herbicide may also be used to help to prevent new plants from forming from seeds. In cool season grasses, there are post emergent herbicides labeled for control of creeping woodsorrel, but a recent University of California publication stated that there are currently no postemergent herbicides labeled for controlling creeping woodsorrel in warm season grasses (Bermuda grass, buffalo grass, or blue grama). In these grasses you are limited to manual removal of the plants and use of preemergent herbicides to prevent seeds from starting new plants.

A healthy, dense, properly maintained lawn will ultimately be your best management method. A healthy, dense lawn will prevent seeds from germinating and compete effectively with the mature plants. However, drought or other injury to the lawn will release this weed to become a problem again. The key is proper long-term management of the lawn.

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Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!