Solarizing and Mulching the Garden

Since we’ve had high temperatures, high humidity, and frequent rain all summer, I was expecting to find the school garden full of weeds. When I checked it this week, I was surprised and pleased with the condition of the garden. There were plenty of weeds around the garden but not in the garden itself. Our preparation for summer in Florida was successful.

In early June at the end of the school year, we solarized the upper level of the garden. The purpose of solarizing is to trap the sun’s rays below a layer of plastic to heat the soil enough to kill the pests, especially the nematodes. To prepare to solarize we pulled out the last of the tomatoes, peppers, and the  few weeds that were growing. We raked all of the mulch from between the rows and added it to the lower level butterfly garden. Next we thoroughly wet the soil in the upper level before covering it with clear plastic. The edges of the plastic were anchored in the soil and weighted with a few bricks. The plastic remained intact all summer and is still anchored on the edges, so there are no weeds in the upper level of the garden.

Last year we didn’t seal the plastic as well around the edge and used a thinner plastic, so we had gaps around the edge and in the middle where the plastic had failed. It was full of weeds at the end of the summer last year. Since our garden soil is still covered with the layer of  plastic this summer, it doesn’t just mean the weeds couldn’t grow, it also means that the solarization process will have killed more of the nematodes than last year. That is good news and should result in healthier plants during the coming year.

The butterfly plants in the lower level has mulch between the plants. The purpose of the mulch is to help hold the moisture in the soil and to prevent the growth of weeds. At the end of this summer our lower level has healthy looking butterfly plants that have thrived in the summer rain and sunshine. There are a few weeds, but the mulch has done what it should to prevent most of the weeds from growing. It will just take a few minutes to get rid of the weeds to have the butterfly garden in good shape again.

Solarization in upper level

Solarization in upper level

Butterfly garden with mulch in lower level

Butterfly garden with mulch in lower level

Cloudless Sulfur Butterfly Caterpillar

Yellow larva of the cloudless sulphur, Phoebis sennae

Yellow larva of the cloudless sulphur, Phoebis sennae

I believe the caterpillar pictured above is the cloudless sulphur caterpillar (Phoebis sennae). Apparently there are variations in colors and patterns for the cloudless sulfur caterpillars. According to an article on the University of Florida IFAS website, the caterpillars  that “feed predominantly on flowers are yellow with black transverse bands”.  It was feeding on the flowers, it has the described pattern, and we often see the sulfur-colored butterflies around the candlestick plants, so my conclusion is that it is a cloudless sulfur caterpillar.

I like the cheerful color of the candlestick flowers and we enjoy the dancing yellow butterflies. Losing a few of the flowers to the munching caterpillars is a fair exchange. Besides, the cassia plants produces many seeds. There are several volunteer cassia plants growing in the front and back gardens so I don’t think we’ll run out of flowers any time soon.

Zebra Longwing Butterflies

We’ve enjoyed seeing the many zebra longwing (Heliconius charitonia ) butterflies this summer. Although this is the Florida state butterfly I haven’t had many in my garden before this year. They visit the firebush and other flowers for the nectar and pollen, but they tend to only lay eggs on the purple passionflower, Passiflora incarnata L.; corkystem passionflower, Passiflora suberosa L.; yellow passionflowerPassiflora lutea L.; and several other passionflower vines. I don’t have any passionflowers in the garden, but someone in the neighborhood must have them. I don’t see any in the front yards, but there must be passionflowers tucked away in a backyard nearby. I may have to add some to my garden to ensure that we continue to have these beautiful butterflies flitting around the garden.

Zebra Longwing Butterfly from Rhonda Carrier on Vimeo.

Read Zebra Longwing on IFAS for additional information

Spotted Oleander Caterpillar Moth

A few weeks ago, we spotted the moth pictured below on the outside wall of the house near the oleander plants. We thought it was a variation of the polka dot wasp moth since it had polka dots on its body, but the red wings were the wrong color. Through my research on the IFAS website, I’ve found that it is a completely different species. The common name is the spotted oleander caterpillar moth (Empyreuma affinis Rothschild). Its caterpillars eat the oleander leaves also, but are usually not in large numbers so the overall effect is not as harmful to the oleander plant as the polka dot wasp moth caterpillars. We’ve only seen this moth once and I don’t think we’ve ever seen the caterpillars. (see link below for more information from IFAS)

spotted oleander moth
Spotted Oleander Caterpillar Moth (Empyreuma affinis Rothschild)

For more information, please read:

Spotted Oleander Caterpillar on IFAS

Polka Dot Wasp Moth on IFAS 

Polka Dot Wasp Moth

oleander caterpillar

Polka Dot Wasp Moth caterpillar on Oleander

We’ve been watching these polka dot wasp moth caterpillars (Syntomeida epilais Walker) on my oleander plants. The young caterpillars eat the underside of  leaves, but avoid eating anything from the veins of the leaves. As they grow, they become tolerant of the poison in the white sap of the oleander plant, which allows the more mature and larger caterpillars to eat the entire leaf.  This is an advantage for the caterpillars since birds avoid eating them due to the oleander chemicals in the caterpillars.

polka dot wasp moth caterpillars

The caterpillars are often found clustered together on the leaves. If there are large numbers of them, they can eat all the leaves on the plant in a few days. The information on the University of Florida IFAS link below recommends that one of the most effective means of control is to cut the branches with the clusters of caterpillars, place the branches in a plastic bag, and freeze them.  Although the caterpillars are poisonous to birds, humans are not harmed if you touch them.  However, avoid touching the white sap from the oleander plant or wash your hands thoroughly after contact with the sap.

Mature caterpillars tend to search for sheltered locations high off the ground. Their bright orange color makes them easy to spot as they climb up the walls of the house. Right now, there are clusters of them under the eves and in the door frame where each has spun its wispy chrysalis structure.

polka dot wasp moth chrysalis

Although the polka dot wasp moth flies during the daytime and not at night as most moths do, they mate and lay their eggs in the pre-dawn hours.

” In this species, female moths perch on oleander foliage and emit an ultrasonic acoustic signal which, although inaudible to us, attracts male moths from great distances. When male and female moths are within a few meters of each other, they begin a courtship duet of acoustic calls which continues until mating occurs two or three hours before dawn.”

We love the polka dots, the iridescent blue of the wings, the bright red abdomen, and the white tips on the antennae. The first time we saw one was on the 4th of July. It looked like it was celebrating with its patriotic red, white and blue colors. We affectionately call these moths the “blue dudes”. I received a photo today from my daughter-in-law of another one that she had spotted and my granddaughter told me, “The blue dude was sitting on the ground.”

polka dot wasp moth

Polka Dot Wasp Moth (Syntomeida epilais Walker)

Polka Dot Wasp Moth from Rhonda Carrier on Vimeo.

For more information, please read:

Polka Dot Wasp Moth on IFAS