Preparing for Caterpillar Season: Milkweed

Guest post by Jill Staake, author of My Florida Backyard

During the chilly winter months in Florida, days can go by without a butterfly sighting, but it only takes a few warm days to bring them out again. In a few weeks, they'll be back in full force, making now the perfect time to prepare your garden to support butterfly and caterpillar populations for the year ahead.

Butterfly enthusiasts know that milkweed is the larval host plant for butterflies in the subfamily Danainae, which includes Monarchs and Queens. In Florida, the most common milkweed available for sale is Asclepias curassavica, known commonly as Tropical Milkweed or Scarlet Milkweed. This species of milkweed is not actually native to Florida, but has naturalized here due to its ability to thrive in our hot and sticky summers. Being a tropical plant, it is not cold-hardy, though it will frequently come back from the roots if you're patient. It also reseeds readily, and also grows easily from stem cuttings allowed to root in water.

Florida also has several dozen native species of milkweed, most found only in the wild and some in very localized populations. Of these native species, the only one commonly found for sale is Asclepias tuberosa, commonly called Butterflyweed. By scouring the internet, I've gathered information on twelve other native species, and found seed sources for three of them. The list below shows botanical name, common name(s), and some general information. Craig Huegel has done a great job documenting many of these species in detail on his Native Florida Wildflowers blog, so for further information and pictures, click the botanical name to be redirected to his blog (or, in a few cases, www.wildflower.org).

Asclepias connivens - Large Flower Milkweed

• Occurs throughout Florida in open wet flatwoods and savannahs, in widely scattered and localized populations
• Requires open and seasonally wet conditions to thrive

Asclepias curtisii - Curtiss' Milkweed

• Extremely rare endemic and endangered species, with localized populations
• Confined to sunny and very well-drained sandy habitats in the peninsula

Asclepias feayi - Florida Milkweed

• Endemic to Florida and found only within the southern half of the state
• Native to well-drained upland habitats, especially xeric flatwoods and sandhills with high levels of sunlight

Asclepias humistra - Purple Milkweed

• Native to the northern two-thirds of Florida
• Prefers well-drained sands and full sun; will rot quickly if planted in moist soils

Asclepias incarnata - Swamp Rose Milkweed

• Native throughout peninsular Florida
• Prefers moist to wet soil habitats in sunny locations, but can tolerate occasional drought once established
• Huegel notes this species is difficult to cultivate from seed, although seeds are readily available in many seed catalogs. In addition to seed, Prairie Moon Nursery offers both bare root and potted plants for sale via mail order.

Asclepias lanceolata - Fewflower Milkweed

• Tall thin species with very thin leaves and small heads of bright orange blooms
• Occurs throughout Florida in open marshes, wet prairies, and savannahs

Asclepias longifolia - Longleaf Milkweed

• Found throughout Florida in pinelands and savannahs with sunny, moist soils
• Easy to grow from seed, though no commercial seed source appears to be available

Asclepias pedicellata - Savannah Milkweed

• Occurs statewide in open upland habitats, such as pine flatwoods and prairie
• Prefers average conditions during much of the year and moist soils during the summer rainy season

Asclepias perennis - Swamp Milkweed, Aquatic Milkweed, White Milkweed

• Occurs in a variety of wetland habitats, including semi-shaded forests
• Requires good soil moisture to prosper; has some drought tolerance but must be provided plenty of water during the summer months

Ascplepias tomentosa - Velvetleaf Milkweed

• Occurs in a variety of well-drained upland sites throughout most of Florida
• A good candidate for gardeners looking to use native milkweeds in a butterfly garden

Asclepias verticillata - Whorled Milkweed

• A drought-tolerant species that thrives in sun or part shade
• Seeds available from Prairie Moon Nursery via mail order

Asclepias viridis - Green Antelopehorn, Spider Milkweed

• This species prefers moist soils and full sun
• Seeds available from Prairie Moon Nursery via mail order

For butterfly lovers in Florida and other states, MonarchWatch.org is a great source of information on milkweed around the country. Here you'll find an in-progress guide to milkweed species, along with detailed growing information. Many milkweeds are surprisingly hard to start from seed, requiring scarification and/or stratification to germinate, and this site provides instructions for both. They also offer a Milkweed Seed Kit for sale that provides four kinds of milkweed seeds, three of which should grow well in Florida.

In a butterfly garden, you can never have too much milkweed. A hungry caterpillar can strip a plant of leaves in just a few days, so plant all the milkweed you can handle to support a healthy butterfly population in your area. You can start now from seeds, or watch your local nurseries for milkweed plants in the months ahead. A patch of milkweed is almost guaranteed to be a butterfly magnet - if you plant it, and they will come!

If you know of a source for seeds or plants of any of Florida's native milkweed species, we'd love to hear about it. Tell us in the comments or drop by the BioWorks Garden Facebook page.

BioWorks in the news

The BioWorks Butterfly Garden and butterfly keeper Kristen Gilpin will be featured in a WFLA Channel 8 segment on cold weather gardening with Leigh Spann. The segment will air on the morning news next Friday January 28th between 5 and 6 in the morning and will be repeated between 6 and 7. If the segment is posted online we’ll be sure to link it here and on the garden Facebook fan page.

Tasks for the winter garden

Central Florida in winter is subject to occasional freezes but is often a place of mild weather in the winter months. In many other locations across the county, winter is the time where you don’t think much at all of gardening. However, in the Tampa Bay area, winter is a great time to get some garden tasks completed that become unsavory in hotter months.

Prep a new garden bed: Have an idea for a great new garden area? Get started on it now. Mark out your garden plot and remove all the grass and weeds from the area, making sure to shake as much soil from the roots as possible. If the soil is very sandy you might consider adding some good compost to the area and turning it into the soil. Turning soil, tilling a garden and tearing out sod are pretty uncomfortable jobs for hot weather.

Mulch: Mulching can be heavy work in the summer, but it has a great number of benefits to your garden. Also, a fresh layer of mulch in the winter helps an empty or sparse garden bed look more groomed and less barren. Here are some benefits of mulch for your garden from the Floridayards website:

Mulch, Mulch, Mulch: Mulch offers many benefits to your landscape. Adding mulch to your landscaping beds is perhaps one of the easiest things you can do to help conserve water, prevent weed growth and improve the look of your yard.
Here are some quick facts about mulch:

• Mulch maintains soil moisture, reducing the need to water established plants.
• Mulch inhibits the growth of weeds, reducing the need for chemical herbicides or other weed control techniques.
• Mulch buffers soil temperature by keeping it cooler in the summer and warmer in the winter.
• Over time, organic mulch decomposes and improves your soil.
• Mulch can be used in place of lawn in areas that are difficult to mow or where grass does not grow well.

Learn more about the Nine Principles of Florida-Friendly Landscaping at Floridayards.org.

Research new plants for the garden: Planting the right plant in the right place is one of the Nine Principles of Florida-Friendly Landscaping. This means that you have to take a good look at your garden areas and determine what types of soil, sun/shade conditions and soil moisture conditions exist. If you have a bed that has rich soil, is in full sun and has constantly moist soil you can then do research on what plants will grow best there. Buying plants that will thrive in your garden means the plants will do better, last longer and will require less watering. Build a chart that shows the conditions in each garden bed an use that to help you find new plants for the garden.

Compost: Compost still breaks down in the winter, just at a slower rate than in the summer. Build yourself a compost bin and start recycling kitchen scraps, coffee grounds and yard waste. By Spring, this compost will provide you with a great way to enhance your soil using your own household trash.

Plant a winter garden: There really are plants that will grow in Central Florida winters, they just don’t tend to be tropical. The occasional freeze might mean you will have to cover part of your garden but some plants will take much less damage from a freeze or frost. Look for plants rated for cooler temperatures and a drier season.

• Herbs that do well in the cool season like parsley and cilantro will spice up your kitchen.
• Cool season vegetables and fruits like broccoli, lettuce, kale and strawberries can turn into salads and extra food for the family.
• Winter annuals like angelonia, salvias, alyssum, snapdragons, pinks (dianthus), and petunias can brighten up a patch of garden.