Bravo for using a gritty mix in your container. Looks very nice!

To get the most compact and bushy growth with short internodes, you'd be best doing the pinching during the Summer (prime growing season). If you prune now, the new growth may be leggy, and you may not get the lower nodes to back bud.

Generally, you need to remove enough of the branch tips to alter the hormone concentration. For some plants, that's a small tip....for other plants it may be the majority of the nodes on the trunk/branch.

Josh

Thanks so much for the advice. This newbie is appreciative.

Perhaps I'll treat this more as an experiment and start a few more seeds, so as to try different times, patterns, and severities of pinching.

Hard to see in the pic, but the lower nodes do show small protrusions that I assume could be potential sites of future lateral growth.

This plant is said to grow in warm areas from desert to tropics, and even to tolerate salt, but all signs pointed to a well-draining mix - and it seems to be working.

acg

That is nice looking plant already - I can't offer any tips, but am interested to see what you will do with it & how it will grow.
Are you planning on planting it/growing in container outside? I see it is annual in your zone. Is it easy to overwinter indoors?
Hope you'll post more about it, and any other you may start from seeds..
Rina

left pic above... first set of leaves.. one or two buds???

if one.. look to the next node...

chose one that has two buds ... however high that may be .. eh???

ken

You don't need to be the bus driver to know what makes the wheels go around. I'm sure a good number of growers know a lot about how milkweed will respond to pruning even if all they use in their predictions is their experience working with other plants. While there are a few plants that don't respond to pruning in ways we might expect (Norfolk Island Pine, for one) most plants (and I mean at least 99%) respond just as you would expect them to respond when you alter the balance of growth regulators that determine whether the plant concentrates it's growing efforts in additive or multiplicative growth. Your plant, is naturally apically dominant, so it wants to grow additively, and it is. To change it's habit temporarily to multiplicative (more branches instead of longer branches) you need to remove the source of the growth regulator (auxin) that is inhibiting multiplicative (lateral) growth. The most significant source of auxin is found in apical meristems (growing branch tips).

Dr Carl Whitcomb often notes there is a "4-inch rule" that applies to pruning containerized plants. He suggests that removing an apical meristem affects the growth of other nodes for a distance of about 4" proximal to the cut. So - removing a branch tip affects the growth on that branch for approximately 4" behind that cut. I have a lit of experience doing hard pruning of plants, in which I remove up to 100% of the green growth on a given branch (or even the entire tree). I can attest that harder pruning of one branch can affect the back-budding response of the entire plant. IOW - the harder you prune, the more latent buds you can expect to be activated.

Also, as noted above, WHEN you prune and how much stored energy the plant has at the time you prune impacts back-budding response. Healthy trees with lots of stored energy will be much more cooperative when it comes to back-budding than plants that are just getting by.

In the picture you posted, I would have either pruned just above the first pair of leaves, then pruned again after the 2 branches that grew from buds in the leaf axils had 3 pairs of leaves - I'd have pruned the secondary branches back to 1 pair of leaves, too.

If I had originally pruned back to 2 sets of leaves, I would wait for a week to ensure bud activation in all 4 leaf axils and would remove the top 2 leaves if it didn't occur in the bottom set.

You really have a lot of time to pinch most plants. I pinch hardy hibiscus at least 3 times. It gives me shorter, sturdier plants and lots more blooms. In fact, I pinch a LOT of plants very regularly to force them to grow in ways I want them to grow, instead of allowing them to do their own thing.

Some plants I've pinched with the specific intent of altering their growth habit:
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Al

Thanks very much for sharing your extensive knowledge. And for those photos of what can be done with proper pinching.

The C. procera seeds came from Hawaii, and it appears - at least in posts from Zone 10 Florida - to be grown there as a perennial in gardens. Although a specific subset of possible growers, comments on monarch-butterfly websites make it appear that only very recently have people in cooler areas been trying to grow this in containers.

For me, it's an experiment. I don't really have a useable outdoor area (even in summer) or window access to effective sunlight, but I had previously grown tropical milkweed (A. curassavica) entirely indoors under artificial lighting.

Other than as a monarch host, it is supposed to have very interesting fragrant flowers and curious seed-pods - at least unusual to someone with little plant-background like this newbie in US zone 6.

So thanks for the advice and encouragement; I'll remember to update as requested.

Update as requested. So far, always growing indoors.

Initially was curious to see what would happen with this particular plant if I didn't follow the above advice: first pinched about 5 nodes up. One bud branch petered out after about an inch, and again a single main continued up. Then pinched right above that to see if the thin stunted second branch might take off. It didn't. One main stem again, like the tropical milkweed in my experience. (First photo.)

"… the harder you prune, the more latent buds you can expect to be activated…[and]…WHEN you prune and how much stored energy the plant has at the time you prune impacts back-budding response." - tapla

After waiting for the plant to be growing well (hopefully having stored energy), I eagerly took the advice to hard prune - in fact to "whack" it as the humorous (heartless? :) Jade growers like to say over in Cacti and Succulents. Right down to the first two latent buds (one bigger than the other) visible above the medium.

Before even one of those two buds grew much, two new stems (within days) punched their way up from under the mix. At first, it was a three-way growth, but the two from down under soon surpassed. As of now the original (center) stem is withering away, while the two stems are still displaying equal growth.

I'm not sure a whack was a fair test of the pinching response. It looks nice now, but I suspect the two stems won't soon re-branch out on their own. I don't expect to achieve anything like in Al's photos, but it would be fun to keep this bushy and branching. Most of the nodes don't visibly show even the tiniest of dormant buds, and the ones that do a single tiny one.

Not quite sure what to do in future, but it should be interesting.

When you cut off a stem, the stem stub (in a very high % but not all plants) usually dies back to the first leaf proximal to the cut, so that seems normal. What seems to be happening in your case is, you have 3 separate branches/stems forming. The sprouts originating lowest on the plant will be more vigorous. They are either getting the lion's share of the water and nutrients or the more vigorous basal sprouts are shading it out. At this point, you can either pinch the center out of the vigorous shoots OR pinch both back to 1 pair of leaves. Try leaving a healthy stub above the leaves. It will die back and you can remove it later. SOMETIMES, if you cut too close to the pair of leaves you want branches to grow from, as the short stub dies back it can interfere with water movement into the new shoot if it isn't well-established

The whack was a fair test of pinching, and there is a latent bud (several, actually) in each leaf axil; however, only one bud at a time is usually activated because once the tissues organize an apical meristem, it starts producing auxin, which suppresses the other buds. If you were to lop that branch off entirely, and the site of the branch was getting good light, the next bud would erupt .... unless an auxin source from above was producing a sufficient amount of auxin to suppress it.

Now, you can get to work on all your plants and use your new tool to keep them nice and full.

Al

As I said in my first post, you should have looked into growing this cultivar. Don't take general advice, always a bad idea! Milkweed from seed is topped at the 30 day mark, not sooner, not later. Also is this one of the toxic milkweeds? Be careful if so. It took me 5 seconds to find that advice. I hate to see someone struggle when given bad info. If you pinched at 30 days 5 nodes would have started growing out. Oh well.

Thank you for sharing your expertise. I find little experiments such as this one, and the helpful and encouraging comments in this forum, are giving me more confidence in dealing with greenery.

Show us the link, Drew ......... There is no physiological reason to pinch at 30 days, and how can anyone predict the number of nodes or leaf axils that would produce new shoots? You can't. A plant grown for 30 days in poor conditions might only be a fraction of the size of a plant grown in optimal conditions, and the number of lateral breaks on each plant could be very widely divergent. It seems the one size fits all advice you gave is exactly what you railed against in your first post.

Plants are VERY predictable in their general response to pruning, but accurately predicting the number of lateral breaks one might expect from a stem truncation of this plant would require a crystal ball.

Al