It's time to vote on our 2017 photo contest! Vote for your favorite photos of the year here!

Asclepias curassavica 'Silky Gold' not germinating

Wheaton, IL(Zone 5b)

I'm having trouble germinating 'Silky Gold' milkweed. Sowed the seeds that I got from a friend's plant on 3/13. Have kept them moist, under the lights and on a heat mat, and still nothing! Don't know if I should put the whole cell pack in a bag in the fridge, or just wait longer. Seeds were kept in the fridge since the fall, so I don't know if more stratification is needed. Anyone's previous experience with this variety would be greatly appreciated!

Galesburg, IL

I don't know specifically about A. curassavica, but most milkweeds do need some cold stratification. Storing seed dry in a refrigerator is not stratification, it is just cold storage. Stratification needs to be done with moist seed. I would spend some time on Google and see if you can find some info on stratification times for A. curassavica. and then put the cell pack in the fridge for the recommended time.

Wheaton, IL(Zone 5b)

Thanks trc. I have done some research on the net about this plant, as I have never grown it, before I sowed the seed. What I found is that most milkweeds do require stratification, but A. curassavica is the tropical milkweed, and it does not. That's why I started it under the lights on the heat. My research indicated it germinates better with warm temps (makes sense with the tropical plant!). When I have trouble with seeds germinating on a variety I've never grown before, I wonder if the seeds were not good, or I am just doing something wrong. Someone else's personal experience is always helpful to me.

Galesburg, IL

Once again, I know nothing about A. curassavica, but the first time I purchased some seed of A. tuberosa I stratified it per instructions and then waited, after about 45 days at recommended germ temps I had one out of 50 seeds actually germ. I figured it was just a very hard to germinate plant and I figured myself lucky to have one healthy plant. Since then I have harvested seed from that plant and started more. They germed at 100% just three days after removing them from the refrigerator. The lesson is, every seed germination failure is not the fault of the person performing said germination and many factors other than experience enter the equation especially when dealing with different vendors/sources.

I spent some time on Google just to see what the plant looks like and found one site that said to stratify the seed for 3-4 weeks and that germination is erratic and could take from 30-90 days at temps between 50-77degrees F, and another site said germination takes from 5-20 days with no stratification.

Some thoughts, I'd leave the seeds you have sown and see if you will get some germination. If you have more seed, I'd start it and just keep it at room temperature and see what happens. If you have even more seed try throwing some in the fridge for 10 days or so and then germ it. Even though it is a sub-tropical plant sometimes a little cold wet treatment will jump start some seeds. If you have planted all the seed you have, then I would put the cell packs/pots into the fridge for 10-14 days and then return them to room temperature for germination.

Thoughts on why no germination yet - was the seed harvested fully mature?? or could the temps of your seed on the heat mat gotten too hot?? If you don't have a thermostat that is a possibility as most mats will raise temps from 10-20 degrees over ambient temps. I use a thermostat on my heat mats and never let them get over 75 degrees.

Hopefully, someone who has experience with this plant will chime in and let us know what has worked for them.

Good Luck.....

Büllingen, Belgium(Zone 6b)

I sowed these seeds indoors, not under lights and not on a heath mat, but they germinated quickly and had a good germination rate. I sowed them in vermiculite.
Although it's tropical milkweed, I think high temperatures are not good. They germinated here at about 64°F (during the night temps went down to 57°F).

But it might be that the seeds aren't viable. If you have some left, try it again without any lights or heath.


Wheaton, IL(Zone 5b)

Unfortunately, I had only a few seeds, and sowed them all, hoping to get at least one plant. I think I'll put the cell pack in the fridge for 10-14 days as suggested, and then take them out again and see what happens. I don't have a thermostat on my heat mats, but have used them for 2 years now with great success and very rapid germination on everything else. I did germinate a different Asclepias with no problem. I'm really wondering if the seed is viable. Last year I couldn't get some Salvia seeds to germinate, and then found out the seeds were bad!

Thanks for all the suggestions. I'll post again if I get any positive results.

Cincinnati (Anderson, OH(Zone 6a)


Sorry to hear of your difficulty with the tropical milkweed, A. currasavica. If you would like to try again, click on the "Hummingbird and Butterfly forum" and just make a polite request for some new seeds, and I'm sure you will get some. They are always ready to help over there.

FYI Asclepias currasavica is a tropical variety of milkweed and does not need (nor probably want) cold treatment. Some say germination can be erratic and might take up to 30 days, but that has not been the case for me.

This particular milkweed is native to Mexico and grows in warm climates and generally pops up after about 5 days when sown in damp warm-ish soil (let's say 75 or 80 degrees). Don't let the soil dry out: cover your seed pot with saran wrap or other plastic to keep it moist.

If you like you could soak the seeds in H2O for a few hours first and then sow them in seeding medium.

As opposed to A. currasavica, other milkweeds such as A. tuberosa and A. incarnata do often benefit from cold treatments for several weeks. These milkweeds are native to the plains states and other cold areas and are perennial in midwestern climates and do seem to have erratic germination for me.

The tropical milkweed A. curassavica (which is the easiest to grow I think) however is not winter hardy in midwestern climates, although a springtime volunteer may result from reseeding or you may get a rare return of a curassavica once in a while.

I start seeds each week during May and set them out into the garden when it warms up. Using a staggard seeding schedule I usually have plants with fresh new tender leaves coming on for the Monarch caterpillars to munch on through the latter half of summer.

Good luck. t.

Wheaton, IL(Zone 5b)

Thanks for your suggestions. Unfortunately, I am not a paid member, so I have not access to the Hummingbird and Butterfly forum.
I really believe that I did not get viable seeds. Hope I'll have better luck next year.

Tucson, AZ

Most milkweed (asclepias) varieties are "self-incompatible" pollinizers. This means that they require pollen from a different plant to produce fertile seeds. A little book called "Milkweed, Monarchs and More" is helpful in understanding the pollination process of milkweed which differs from many other plants. I, too, planted seed from my plants without success, until I learned that they WILL produce seed but it will not be viable. Cold stratification depends somewhat on variety, but again most do well with that method. Currasavica is sub-tropical and does not need cold stratification is seed is fertile. It takes more than one plant of the same variety to produce fertile/viable seed. Plant several and you should see more successful seed production.

This message was edited Apr 11, 2014 3:27 PM

Arroyo Grande, CA(Zone 9a)

I have fresh yellow curassavica seed if you want to give it another try. They are really easy germinators so I don't know what the problem was. I grow curassavica in my garden and I get a few volunteers every year, even though I try to collect most of the seed. They don't need a freeze and you should have no trouble starting them early indoors or just planting them in the garden once the weather gets warmer. They grow to full size quite quickly. Just send me your address if you'd like some.
[email protected]

Post a Reply to this Thread

You cannot post until you , sign up and subscribe. to post.