Timely Tips for May – Part 2

By Andy Wilson, Horticulturist, Pinellas County Extension

Got Oleanders? Got Caterpillars?- Oleanders in our area are routinely attacked by oleander caterpillars, orange caterpillars with tufts of long black hairs scattered over the body. They are voracious feeders and they can strip most of the leaves from the plants in a surprisingly short period of time. The damage is unattractive but not life-threatening to the plants. Applications of sprays containing Bt (Bacillus thuringiensis) generally give good control. There are several generations of these caterpillars per year so it is helpful to check the plants regularly for them.

Flower Thrips on Gardenias- Gardenias add a heavenly scent to many gardens at this time of year but the life span of individual blossoms can be shortened by flower thrips. These small insects feed on the sap of the flower petals, causing the petals to turn brown prematurely. The thrips can also invade flower buds before they open, sometimes causing the buds to drop off without opening. Spraying the plant with a systemic insecticide like imidicloprid or acephate will usually control them.

Thrips on Crotons- Types of thrips that feed on plant leaves are often a problem on crotons in the spring months. On crotons the damage usually shows up as a loss of color in the lower leaves, with leaves eventually turning a tan color. Infested leaves will have small brownish spots of excrement on their undersides. Damaged leaves drop off the plant beginning at the base of the stem moving upward. Leaf feeding thrips can be controlled with several products including light horticultural oils. More information on thrips can be found here: http://edis.ifas.ufl.edu/MG327

Tree Mummies?- If the trunk or branches of one of your trees develops a gauze-like or silk stocking-like covering there is no need to panic. The tree will not be harmed. The webbing is spun by psocids, small insects that feed on lichens that live on the trunks of trees. Psocids produce the webbing to protect themselves from the elements while they feed. Although the webbing can look quite eerie, psocids do no harm whatsoever to the tree they’re on and no control is needed. Eventually the webbing will weather away.

Summer Color - For color in the summer landscape consider these heat tolerant bedding plants: vinca, globe amaranth, amaranthus, moss rose, purslane, celosia, melampodium, Dahlberg daisy, ornamental pepper, salvia and wishbone flower. It’s helpful in work 2 to 3 inches of organic matter (peat, compost, etc.) into the soil before planting. This improves the water and nutrient holding capacity of the soil. More information on selection, planting and care of bedding plants can be found here: http://edis.ifas.ufl.edu/MG319

Mango Harvest- Early maturing varieties of mangos like ‘Zill’, ‘Edward’, ‘Saigon’, ‘Florigon’ and ‘Earlygold’ are ready for harvest as early as May. To determine whether the fruit is mature enough for harvesting look for fruits in which the shoulders and nose of the fruit have “filled out” or broadened. Often there is a touch of color in the skin of the fruit at this time (on varieties that color at maturity). Mature fruits will usually ripen to eating quality in 3 to 8 days indoors at room temperature. Once they are fully ripened the fruits can be refrigerated for later use.

Timely Tips for May - Part 1

By Andy Wilson, Horticulturist, Pinellas County Extension

May is a month of transition from spring to summer. For many people this will be the last time until fall to enjoy having windows open. As we all know, hot and humid weather is just around the corner. It’s a good time to get some things done in the landscape before summer’s heat arrives. Here are some lawn and garden tips for May.

Irrigation- Since May is a warm and usually dry month, St. Augustine grass lawns will quickly show drought injury if irrigation heads get clogged or in some other way stop working. Although diseases and insects can cause browning of lawns, if the browning follows the same pattern as the sprinkler head coverage it’s time to check the heads. It’s also a good idea to calibrate the system to make sure that about ¾ of water is being applied per irrigation. When watering established lawns the goal is to wet the soil to the depth of the root system and in our sandy soils this usually requires about ¾ inch of water. If much more than this is applied in one watering the water quickly percolates below the reach of the grass roots and is wasted. Calibrating an irrigation system is not difficult. Find out how here: http://edis.ifas.ufl.edu/LH026

Mulching- The dry weather of May is usually followed by the beginning of the rainy season sometime in mid- to late-June. Frequent rains will encourage weed seeds to germinate. Applying about a 2 to 3 inch layer of mulch now will help to discourage this. Several kinds of mulches are available including pine bark, pine straw, melaleuca, and recycled yard waste mulch. Pinellas County distributes free recycled yard waste mulch at several sites around the county. A list of locations with hours of operation can be found here: http://www.pinellascounty.org/utilities/PDF/mulch-flyer.pdf

Don’t Let Your Palm Go Topless- Although hurricane season begins June 1st, it is not a good idea to give palms what is commonly known as a “hurricane cut”, pruning off many green fronds, leaving the palm looking like a feather duster. Removing large numbers of green fronds stresses the palm by reducing its ability to manufacture food for itself. It also removes significant amounts of nutrients with the removed fronds, often worsening any existing nutritional deficiencies. If this is done repeatedly it can lead to bottlenecking, an unattractive constriction in the trunk. It is better to remove dead fronds as they appear throughout the year. Observations of wind damage to palms after some of the hurricanes that have occurred in recent years indicate that damage to palms that have been “hurricane cut” actually tends to be worse than on palms that faced the storms with a full complement of fronds. More information on pruning palms (and other aspects of palm care) can be found here: http://edis.ifas.ufl.edu/EP119