HUNTSVILLE, AL - - Dear Harvey,
I have tried to grow Butterfly weed from seed the last couple of years without any success. I let the seed pods pop open and then cover the seeds with mulch but I have not had any luck with them germinating – any ideas? Thank you, George H.
First I want to thank you for trying to grow Butterfly weed (Asclepias tuberosa ass-KLE-pee-us too-ber-OH-suh) in your garden. This is a vital native wildflower in that it is the host plant for the Monarch butterfly. What that means is that the adult female Monarch will lay her eggs on Butterfly weed and the emerging caterpillars (the larval stage) will eat this plant as it grows. Butterfly host plants can be very specific and it is important that we as good conservation stewards make sure that the Monarch (and other native butterflies) has enough food sources to keep the life cycle going. As more and more of the Butterfly weed's native habitat is lost to development or large-scale agriculture, this important wildflower needs to find willing gardeners to nurture, propagate and enjoy this beautiful and very useful plant. The good news is that it is a great garden plant in its own right so including them in your garden is not that hard of a task.
As to your dilemma in trying to grow new plants from seed I would recommend this strategy. Collect the seed pods just as they are about to burst open. As you have noticed the pods are full of tiny, flat, brown seeds attached to a tuft of hair. This “hair” allows the seed to be blown on the wind for dissemination much like dandelion seeds. This is an effective way of moving seeds from one place to another, hopefully spreading the reach of Butterfly weed in the wild.
After collecting the seeds I would place them in a zip-lock bag with moist potting soil. The seeds need a period of cold stratification (like we mentioned with the dogwood seeds a few weeks ago) so place them in the refrigerator for two to three months. This is an important step in the process of germination and my guess is that your seeds did not receive an adequate cold period to satisfy their needs to allow germination to proceed. After two to three months you can remove the seed from the refrigerator, sow in flats and cover lightly with fresh soil mix. Using a heat mat will greatly enhance germination but if you do not have one then placing the flat on top of your freezer or refrigerator will also work. The top of these appliances is always warm and this helps many seeds to germinate quicker. Be patient and do not over water – it will take several weeks for seed leaves to appear and these perennial plants will grow much slower than say annual flowers or vegetables that many of us are used to germinating. After several months of sprouting you can transplant these seedlings into individual four inch pots for growing through the rest of the season. In fall I would transplant into your garden beds.
This time of year is a fabulous time to collect seeds and begin the process of growing new plants for your own garden or sharing with others. I have received several questions recently about seeds and one thing that stands out is how incredibly diverse and wonderful nature truly is. With the Butterfly weed you have these long seed pods with literally hundreds of seed packed inside. When the time is right the pods break open and the seeds travel in the wind with their own little parachute or sail. Another way seeds are dispersed is by birds and animals, whether by hitchhiking on their fur or by traveling through their digestive system. We all know birds eat many fruits and berries and then “poop” out the seeds as they fly around. Just recently I received a question from a local hiker that kept finding piles of seeds in the scat (droppings) of some animal on the trails of Rainbow Mountain. The seeds were from our native Persimmon tree and a favorite food of coyotes, deer and raccoons. The tart Persimmon fruits fall to the ground and these animals feed on them at night and spread the seed in their droppings. I guess one could say that they have their own little supply of fertilizer with them and that is often why you will find a cluster of seedlings growing together in the wild.
I hope this has given you a few suggestions to try with your Butterfly weed seeds – I marvel at the incredible diversity one finds among the entire plant world in how they prepare for perpetuating the species.
This week in the garden:
• Check soil temperatures before planting tulips – best to wait until temperature drops below 60 degrees F.
• Fertilize fescue lawns at the rate of one pound of actual nitrogen per 1000 sq. ft.
• Store tender summer bulbs and tubers like dahlias and caladiums (also elephant ears and cannas) in dry peat moss in a cool, dark spot with low humidity – a basement or garage may be perfect
I look forward to answering all of your gardening questions. Please send your inquiries via email to firstname.lastname@example.org. For those of you who prefer regular mail, please send to Harvey Cotten c/o The Huntsville Botanical Garden, 4747 Bob Wallace Ave; Hsv, AL 35805. The Garden’s website – http://hsvbg.org/