Is Dog Vomit Slime Mold Harmful To Garden Plants

'Dog vomit' slime mold is unsightly but harmless, feeding on your mulch. [Connie Timpson/UF/IFAS]

I keep seeing things in my yard that shouldn't be there, like some yucky yellow stuff. What is it?

Rain, humidity and warm temperatures are the perfect petri dish for slime molds and many forms of fungi. Yellow slime mold, commonly known as "dog vomit," is often mistaken as a form of fungi. It is not.

That bright yellow on your wood chips may seem yucky to you. If you are feeling generous, you might see it as an interesting abstract painting laid down among your mulch. It loves mulch, feeds on mulch, is pretty much always in your mulch, but only shows itself under the right conditions. If you hate the way it looks, just rake it out. It will go through different stages from yellow to a sand color and then disappear. Do not be concerned, it will not harm your plants. With the perfect conditions. you are very likely to see it again. For more on this rather unusual stranger in your garden go to: https://herbarium.usu.edu/fun-with-fungi/slime-molds.

When it comes to fungi, it is a most challenging field of study. Some fungi attacks trees, turf, tomatoes and soil. But they also put good things back in the soil. If you throw them in the compost (even ones you are not sure are harmful to humans) they will aid in breaking down carbon-rich material such as wood chips and leaves.

There are many mushrooms that look delicate and edible – but DON'T eat them, they may be deadly. For an extensive look at what could be good, bad or poisonous, go to: https://www.fs.fed.us/nrs/pubs/gtr/gtr_nrs79.pdf.

Some mushrooms act as diagnosticians, and if we look carefully, they will predict trouble for a tree. When trees begin to die, the mushrooms move in to feed on various parts of the rotting wood. Conks, a form of fungi, are tell-tale signs that the tree has decay and may come down in a heavy storm. Look for other weaknesses like dead branches, and deep splits in the trunk of the tree. The visual sign of decay and instability come right along with the presences of conks and other fungal feeders. For more go to: https://edis.ifas.ufl.edu/ep507.

What's eating my gorgeous canna lilies? I hate seeing them look ragged.

The biggest and most aggressive pest to canna lilies is usually the canna leafroller. Looking at your pictures, we can rule out those culprits. If you look very closely, you can see tiny ants feeding off honeydew, a sugary substance excreted by piercing-sucking insects. Look for tiny white bumps, yellowing leaves and often white powdery wax secretions. In this case, it's a gathering of quickly reproducing whiteflies. You will need to take immediate action because they stick around as long as four weeks in summer. They cause damage by piercing the leaves with their needle-like mouthparts and then sucking out the fluids, causing the plant to look like it is going to lose its leaves as they become yellowed and ill. If you see those tiny ants feeding on the honeydew, it is a pretty good indicator you're your plant is infested with one of the piercing-sucking insects such as aphids, scales or whiteflies.

The solution: Spray both the top and bottom of the leaves with a horticultural soap and oil mixture (2 tablespoons of each to a gallon) or an insecticidal oil such as neem oil. Either should bring relief to your plants. Read the labels and follow the directions closely. Be sure you spray directly down on the whiteflies so that none can fly away during the spraying process. The horticultural oil literally smothers the whiteflies, and in a short time you will begin to see healthy plants and blooms. Keep in mind the dead insects can remain for several weeks.

There is one more step. Pull up and bag any weeds that are growing around your cannas. If the weeds are infested, they could re-infest the cannas. Check out nearby ornamentals. If their leaves are chewed, yellow, have bumps and white waxy or black sooty material, spray those plants as well. This process works well for nearly any ornamental plant in Florida. For more on how to take back control of your garden go to: https://edis.ifas.ufl.edu/in197.

How many times a year should I fertilize my St. Augustine lawn?

That is a very timely question today, because the next two weeks are the last of the fall fertilization time for your lawn. In October your St. Augustine grass will begin its annual winter dormancy and after that the roots will not be able to easily absorb nutrients until spring. To answer your question specifically, three times a year is the St. Augustine fertilization schedule for North Florida. Those three times are Spring, Summer and Fall.

If you are fertilizing yourself, be sure to carefully read the directions on the package about amounts of application, usually per 1,000 square feet of turf. The most important number is nitrogen, the first of the three numbers on the bag. The second number is phosphorous and the third is potassium. See University of Florida publication https://edis.ifas.ufl.edu/lh014 for plenty of great information on fertilizing your lawn.

Connie Timpson is a volunteer master gardener volunteer with the Duval County Extension Service and the University of Florida/IFAS. If you have gardening questions, you can speak to a master gardener from 9:30 a.m. to noon and 12:30 p.m. to 3:30 p.m. Monday through Friday at the Duval extension office at (904) 255-7450.