Joy Derksen: September Gardening column

Our rains have finally started in Manatee County and they’ve come in a variety of levels — from 9 inches near the shore to 55 inches in Myakka fields.

Geiger trees (Cordia sebestena) remain in bloom. The trees are a Florida native with bright orange flowers against dark evergreen leaves. The Geiger is salt-tolerant and a relatively short tree that should be used more frequently in this area.

Although it doesn’t like frost, a cousin (Cordia boissieri) with white flowers and yellow centers tolerates temperatures in the high 20’s. In flower gardens, the Blackberry lilies are in bloom, as are heliconias.

St. Augustine lawns are suffering from various problems. Take-all Root Rot seems to be destroying many lawns now. The trigger for the disease is high rainfall and stressed turf grass. Research has shown that too much herbicide (weed killer) on St. Augustine also provides enough stress to trigger this fungal disease. Initial symptoms are yellow or light green patches in the lawn. The plants are easily pulled up because the roots are dying. Healthy roots are white, but with Take-all Root Rot they become off white and then dark brown to black. This is distinguished from Brown Spot disease where the grass leaves come off the stolen (stem) when you pull on them and the grass remains rooted.

Systemic fungicides (Axoxystrobin, myclobutanil, propiconazole, thiophan methyl, triadimefon) are available, but are not as effective as good lawn management in controlling the disease. The University of Florida has a publication with additional help at http://edis.ifas.ufl.edu/pdffiles/lh/lh07900.pdf.

If you are looking at large patches of dead grass, this could be an opportunity to replace the sod with a landscaped island of shrubbery, trees, flowers and mulch. The islands are usually more attractive and less work than grass. Florida Yard and Neighborhoods and Master Gardeners would be happy to consult with you about Florida-friendly plants that would fit your yard.

Start planning

It’s time to start preparing for the winter gardening season. Select an area for garden beds that gets at least six hours of sun and has good drainage. Remove and compost tired plants, incorporate 2 to 3 inches of organic matter into the soil, and add a complete fertilizer (6-6-6). Plan out your garden on paper and plant at the end of the month or the beginning of October to avoid the worst of our insects and heavy rains.

Beans, beets, broccoli, cabbage, collards, corn, cucumbers, eggplants, Asian and American greens, lettuce, onions, peas, pepper, white potatoes, winter squash, tomatoes and turnips are some cool-weather crops.

For more detailed instructions go to http://edis.ifas.ufl.edu/VH021 for a Florida vegetable gardening guide or ask your local Master Gardener’s for one (722-4521).

Start your winter herbs. Basil, mint, tarragon and rosemary will take both the heat and the cold.

Set in cold weather flowers such as alyssum, baby’s-breath, calendulas, pansies, petunias, phlox, snapdragons, sweet peas and violas. More information on bedding plants is available at: http://edis.ifas.ufl.edu/MG319.

This is a good time to divide and reset perennials such as African iris, amaryllis, gerberas and day lilies.

Prune back lengthy rose canes and dead, dying twigs for better fall bloom. This is the last time you should prune bougainvillea and poinsettias for winter blooms. Keep an eye out for evidence of leaf roller caterpillars on the bougainvillea. They eat at night and roll up a leaf to hide during the day. Rolled, ragged or no leaves are all signs these caterpillars have been busy. Treat with Dipel or Thuricide (bacterial products that only affect caterpillars and mosquito larvae).

Fertilize lawns and woody shrubs with a long-acting fertilizer. Azaleas and camellias should be fertilized with their own special product as they need the boost to live well in our alkaline, sandy soils. Palms and ixora should be fertilized with a palm special product with minor elements. Citrus also need fertilization to produce healthy blooms and fruit. Do not fertilize if a tropical storm is on the way. Wait until after the rains pass so that your expensive fertilizer does not wash down the drain and out to sea. Often what is good for the environment is also good for the wallet.