Asclepias Propagating Techniques
Randy Johnson Organics
organicrandy@gmail.com
214-584-0565
* Collect seed from local/regional sources. Make sure the seed is ripe by catching the pods just as they begin
to split. Never harvest a pod until it begins to split. Don't rush this step; let that seed fully mature to ensure a
vigorous seedling. Leave some pods. Never harvest every pod in sight as these are a very important food source
for many insects which utilize seeds as food. Milkweed bugs are probably the easiest example of that. The
insect diversity this genus attracts is truly incredible.
* Concentrate on the least finicky variety that will grow in your area. Here on the Blackland prairie I collect
the seed of three species, A. viridis, A. oenotheroides and A. asperula but the easiest to grow is the viridis so
that will be the species I will propagate initially if I am asked. I will grow all three because I want that
biodiversity but the initial thrust should be to get lots of milkweed in the ground with what is easiest to produce
and has the best chance to survive; some of these species are more sensitive than others.
* Plants produced in the spring should not be installed until the fall, post Monarch migration; best case
scenario is to release one-year old material. Plants that are installed before adequate root development have a
very difficult time surviving oviposition. A mature root system can support hosting Monarch (and many other
species, not just butterflies) caterpillars. A lot is asked of this plant from a lot of different sources. It needs that
mature root system to make it and this just addresses supporting native fauna. Throw in some tough climatic
conditions and the plot thickens. Patience will pay huge dividends here.
* Cold-moist stratification (CMS) is required for all of these species. CMS is a method of breaking the 'colddormancy' of a seed at the same time providing the water needed to begin germination. Cold-dormancy means
that a seed must undergo a certain number of 'chill hours', hours below a certain degree, before they will
germinate. It's good strategy to keep a seed from germinating too soon in the season and tempting death by
frost. For any species of Asclepias in Texas which requires stratification, thirty days will suffice. An inert
material like play sand will work and the key thing is moisture level, you want enough available for the seed to
absorb but not so much as to cause rot or fungal issues. Wet the sand enough to just form a drop when you
squeeze a fistful. Use clear zip-lock baggies and put enough so that each seed is surrounded by the wet medium.
You want good contact so the seed can absorb, or 'imbibe', water. When water passes through the seed coat and
is absorbed by the embryo germination has occurred.
* Mix the seeds and the wet sand thoroughly; squeeze all the air out of the baggie making a tight roll. I mark my
baggies with a Sharpie the species, the date of stratification and the removal date. Once you remove them from
the refrigerator after stratification and they get warm, they will germinate very quickly, within 5 -7 days. You
can plant them directly in the ground or into pots for formal propagation.
* I timed my stratification so that I sowed my seed the first of January; I grew in heated greenhouses
WITHOUT supplemental lighting. I emphasize this for a very important reason: Under normal circumstances
this seed would never germinate in January for various reasons but the key thing here is that the sunlight is
indirect and weak this time of year and without strong supplemental lighting these seedlings will get lanky.
Keep the air moving to help stiffen them as they grow and put them in your brightest house for best results.
LED fixtures burn cool, are low consumptive lights which produce a lot of lumens, these would be a wise
investment if you plan to grow very early on the year.
* Grow exclusively 100% organically. Follow Mother Nature here without exception, no reason not to and it
guarantees a healthier plant better able to survive after installation. I highly recommend native soil from the
same locations as the seed source with which to inoculate your growing medium. The soil biology will be
geared to that soil type and that region and these two entities co-evolved. It doesn't take much so don't think
you will need dump trucks, a little is all you will need because you introduce this amendment at the germination
step. I mix it in the medium that composes my seed flats which involves very little material, maybe 4 cups, to
that I would add a tablespoon of native soil and mix evenly. My second choice would be worm castings but get
biology in the medium in which you germinate, many fungal associations, if they occur, begin with the radical
of the seedling.
* Expect aphids. They can overwhelm both seedlings and adult plants but especially the seedlings. A gentle
spritz of water and liquid ivory soap does the trick but rinse-off that residue. This can be done with a hose-end
sprayer or a pump-up spray rig but it is best done with a gentle touch by hand. This genus sometimes needs a
little nurturing so be prepared to spend some time doing hand-work. Best is to employ natural IPM methods
such as Lacewings, Syrphid Flies and parasitoid wasps. When these beneficials are present, I find that the
aphids dominate at the beginning but over time the beneficials really do a number on them. The plants don't
always look great but they co-evolved with this and I see it all the time in the wild. Don't over-freak on the
aphids.
* Install these plants in close proximity, form colonies. Don't crowd them of course but don't make it a
marathon for a foraging caterpillar to find the next plant. These guys often finish a plant and need to move on
to find more milkweeds. Plant them with this in-mind. Be very careful to not break that taproot when depotting the thing and DO NOT attempt to uncurl a curled-up taproot or be very careful if you try, you can tease
it a little but err on the light side.
* There are many techniques for starting these plants; I used a seed flat for germination and then I transferred
by hand the seedling to its initial container. Use something as long as possible. I used 16oz cups because they
were tall and thin, 4" pots are terrible as the tap root coils at the base. Point here is to give that taproot as much
length as possible in which to grow. I think the 'cone-type' containers that tree seedlings are grown-in are what
I will try next.
* DO NOT OVERWATER THIS GENUS unless it is one that likes wet conditions. This plant likes to dry
between watering, let that happen. I lost more plants to careless watering than I care to remember. An aside: I
found watering to be the hardest philosophy to impart to workers that I trained; you would think I was teaching
them nuclear physics.
* I offered my plants seaweed/fish emulsion and vermicompost tea exclusively and never had any issues, what
you use is your choice but I would highly encourage some type of compost product for the soil biology; In my
opinion, this is a huge difference maker and should not be over-looked.
* You will probably need to consider some type of protection for the growing plants from butterfly
oviposition, I like a physical barrier but Bt can be used. This is most crucial during seeding development; after
they have been bumped to their final container and have grown a bit they can handle a caterpillar for a while. I
had the luxury of having mature plants in The Gardens on which to transfer hungry caterpillars. I suggest
growers provide a healthy patch of Asclepias curassavica for just this purpose. I don't suggest this species for
planting in the wild but for a Monarch nursery/transfer station, I am fine with it for this purpose. It produces
tons of foliage and can support a lot of caterpillars. I love this over BT because I can still get the butterflies and
keep my native stuff relatively unmolested and stress-free.
This document cannot be re-printed without permission from the author, Randy Johnson.