Issue: June 1, 1996

Using fallen leaves

I have a lot of leaves which have fallen in my lawn. I have a leaf blower/vacuum that sucks up the leaves and grinds them into a mulch. What can I do with the mulch? Is it a good idea to sprinkle them over the soil beds that contain flowers and shrubs?

Fallen leaves, shredded or intact, are a valuable resource. These leaves can be used as a mulch to protect perennials through the winter. In regions with more moisture just be sure that you don't encourage fungi to attack your perennials. You can protect your plants by adding the leaf mulch after the ground has frozen or at least after the temperatures are cool. The mulch then keeps the soil at a more even temperature which is desirable for most plants. In dry climates, the mulch will also help hold moisture in the soil. Many of our perennials are active below ground even when they are dormant above the surface. Moisture is necessary for root development and the activities which occur result in flower development inside bulbs. If the leaf mulch holds too much water, you may find it wise to remove the mulch in the spring just as growth begins to avoid disease problems. Experience will tell you if this is really necessary for the plants you are growing.

Alternate freezing and thawing is reduced by a thick mulch layer. This reduces the "frost heaving" of bulbs, perennials, and newly planted shrubs from the soil. Remember that the mulch will keep the soil cooler longer into the spring and delay growth and flowering. This may be desirable or undesirable.

The leaves will slowly decompose through the winter, releasing nutrients into the soil to be used by your garden plants in the spring. When you remove the mulch in the spring or if you do not use the leaf mulch, composting the leaves would be a wise decision. By composting the leaves, you can generate your own soil amendment to improve your soil by increasing its nutrient and water holding capacity and return some nutrients to the soil. The shredding by your leaf vacuum will speed the composting process whether on-site as a mulch or in a compost pile.

Ficus benjamina sap making mess on carpet

I have a Ficus benjamina in a well-lighted indoor location. There is very little leaf drop, but the tree has a great deal of sap running off the leaves onto the carpet. Can you tell me the cause and how to avoid it?

The cause that comes to mind is an infestation by scale insects. Remember, I haven't seen your plant, so this is a guess based on the information you provided. While aphids can produce honeydew (the clear, syrupy, sap-like substance you are describing), Ficus are more likely to be infested with scale insects. These will appear as brown bumps on the twigs and leaves which can be scraped off with a fingernail.

Scale insects are difficult to control, especially if they have spread to other plants in your collection. However, there are pesticides which can be used to treat scale insects. You should be sure to select one which is made for use on houseplants in the house. Insecticidal oils and soaps may be your best option while the plants must be kept indoors. You will have to treat frequently, but you should at least be able to minimize the damage until the weather warms in the spring. Then you can take the plants out into a shady place for a few days while you treat with products which you can't use indoors.

If you don't find scale insects, take a sample of twigs with leaves to your local county Cooperative Extension Service office to diagnose your specific problem and recommend the appropriate treatment.

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!