Spring’s showers bring slime

Physarum cinereum is the second most common slime mold, often seen on turfgrass during warm, rainy weather.

It looks like something from another world, conjuring images from a 1950s horror flick. It takes the form of sickly yellow blobs inching toward favorite garden specimens, or black gelatinous beads clinging to grass blades.

Is it an alien life form or a greedy fungus ready to wreak havoc on the plant kingdom? No, they are just harmless, fascinating slime molds taking advantage of the warm, wet weather we recently have experienced in the Lowcountry.

Once categorized by scientists as fungi, now slime molds are classified by taxonomists as belonging to their own group, Protista. They pop up out of nowhere in gardens, on mulched surfaces, in lawns and sometimes even on telephone poles and wooden fences.

Slime molds thrive in rainy, warm weather often seen in our area in the spring and fall. They consume dead organic matter, protozoa, fungi and bacteria found in woods, fields and gardens.

The fascinating part is that they move and organize themselves in ways that inspire artists and compel scientists and mathematicians to use them to research gene sequencing, computer modeling and medicine.

“Dog vomit” slime mold truly describes the appearance of Fuligo septica. This particular slime mold often elicits panic for gardeners and even some pet owners. Instead of immediately thinking something is wrong, I suggest that something may be right in your garden if you have slime molds forming.

How can something so grotesque be a good thing? Healthy, fertile soil contains billions of tiny life forms. One of these might be the reproductive spores of slime molds just waiting for the right conditions to germinate and become tiny, mobile cells. Like true sci-fi, these little cells move together to form large blobs of protoplasm, known as plasmodia. The interesting thing is that while each cell has a nucleus, no one is in charge. It is fascinating that they find each other and form groups with no leader.

Scientists are studying this phenomenon, but you can enjoy it with no lab equipment and no fancy science degree. Observing the molds for a few days and recording their movements provides an excellent opportunity for any curious gardener to observe nature at work.

When it’s still wet outside, the “dog vomit” slime mold organizes itself into a plasmodium and begins to creep along the surface of logs, mulch or soil, feeding on favorite foods and rejecting the things it doesn’t like, such as living plants.

When the sun comes out and the weather turns warm and dry, so does the “blob.” Before it disappears into a dry dusty spot, it releases spores for the next generation, which is precisely why there is no chemical control or “cure” for the common slime mold. Water disperses the mold, so if you truly can’t stomach it, the best thing to do is to gently lift it with a shovel and relocate it to the woods or to another out-of-the-way spot.

The second most common slime mold is Physarum cinereum, often seen on turfgrass during warm, rainy weather. This mold often elicits a strong reaction from gardeners who are convinced this “fungus” is killing their lawn. While P. cinereum can be found on nearly any weed or grass in your lawn, this harmless slime mold is most commonly seen on St. Augustine and Bermuda grass.

The purple spores of P. cinereum form inside grayish-white fruiting structures that drop onto thatch, forming a mass of protoplasm that enjoys the abundant organic food source below. To the unsuspecting gardener, this mass looks like quivering sacks of gel and may cover one blade of grass or a larger portion of the lawn.

Even the most pristine lawn can host these interesting organisms because they leave behind spores for future molds to form. There are no chemical controls available, but if you feel compelled to do something, sweeping the masses off with a broom or raking them off is your best option. Watering and mowing will spread the slime molds, making future colonies a sure bet during the next rainy period.

The Summerville Master Gardeners will host an “Ask a Master Gardener” event 9 a.m.-noon every Friday in May and June on Hutchinson Square in downtown Summerville. Bring soil samples, insects for identification, or other gardening questions. In case of rain, find them at Ace Hardware on Trolley Road.

You also will find Master Gardeners around town at the Mount Pleasant Farmers Market on Tuesdays at Moultrie Middle School and at the Charleston Farmers Market at Marion Square on Saturday mornings.

The Clemson extension 4-H History Explorers Camp will give youths ages 8-12 a chance to explore some of Charleston’s most famous historical sites and learn what life was like for Colonial Charlestonians.

Activities include a walking tour to the Aiken-Rhett House, Provost dungeon and St. Michael’s Episcopal Church; a boat ride to Fort Moultrie; a visit to the Charleston Museum; and an opportunity to learn authentic weaving techniques used to make sweetgrass baskets and much more.

The camp will be 8 a.m.-4:30 p.m. July 15-19 and will cost $125. To register, contact Jennifer Schlette at jschlet@clemson.edu.

Amy L. Dabbs is the urban horticulture extension agent and Tri-County Master Gardener coordinator for the Clemson University Cooperative Extension. Send questions to gardening@postandcourier.com.