Jade Wacking Theory

15 years ago

There has been a lot of talk recently about Jade wacking. Most often this is recommended to make the lower limbs grow thicker faster. The loss of younger leaves at the top removes inhibition of lower growth, resulting in the formation of new branches, but does severe pruning actually increase the rate of increase in stem thickness?

This is what I wrote recently in a thread about wacking some relatively small plants:

I don't think any of these are large enough yet for a major trim. That will reduce the number of leaves (where all the food is made), and it takes the plant a while to recover. A plant left alone in strong light, a good soil mix, with proper watering, and light fertilization in early spring and fall, will probably grow thicker faster than a plant of the same diameter after a major trim. Trimming makes limbs look bigger than normal because new growth appears on older limbs. Plants I have wacked have all been 6-10 years old before the first cut. Your plants are much smaller and thinner than four year olds in my backyard. I think you should not trim at all, just concentrate on growing them well.

So, there you have my argument: the effect of wacking is to stimulate branching, and those new branches, being younger and thinner than the older stems, make it appear that the plant has a thicker trunk. I do not think trimming makes the stems grow thicker than they would without a trim. In fact, I believe severe trimming probably slows the rate of stem thickening compared to an untrimmed plant, so severely trimming young plants is not the best way to thicken stems. A plant alone in full sun with a full set of leaves will have thicker stems than a similar plant that had a severe wack job.

This opinion may be contrary to the beliefs of the many who think that severe pruning actually increases the rate of stem thickening. I hope this prompts an interesting discussion. Let the games begin ;)

Brad

Featured Answer

greenman28 NorCal 7b/8a

15 years ago

Hey, Brad, thanks for introducing this Thread!

I see whacking, primarily, as a means to focus growth toward the trunk when the branches
have become long and skinny, either from simple aging or from etoliation in low-light environments.
As you say, the "trunk chop" is a time-honored bonsai technique to produce trunk taper.

Now, here's how I think that whacking stimulates trunk growth.

By encouraging lower nodes to bud, branches closer to the soil line begin to grow.
I consider these to be "nurse" branches that keep the growth activity concentrated
down low, thereby increasing the thickness/vitality of the trunk locally.

I've also wondered if whacking/defoliating a plant might mimic heavy animal browsing in nature.
Perhaps the plant thickens its trunk to better hold moisture during times of leaf-loss;
or perhaps the trunk thickens against mechanical injury from those browsing animals.

I do believe there is some wisdom in allowing Jades to grow rampant for a time.
As branches extend away from the central trunk, the weight causes the branches to strengthen
at various attachment/stress points.

Josh

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Comments (11)

caudex1
15 years ago
I'm in the "let the plant grow till gets the girth before you chop" group. As in my large variegate, the main stem was not touched for 20+yrs. Did not prune it at all for 15, just let it grow.
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greenman28 NorCal 7b/8a
15 years ago
Another key to sizing-up Jades (and many other plants) is free root-run...whether in-ground or in larger containers.

With large containers, however, one must be sure to create a soil-mix with excellent drainage.

Josh
zachman
15 years ago
I am very interested in the logic behind whacking jades. I have had some success with pruning, but I am unsure about timing. I have heard conflicting information about the best time to prune: some say jades can be pruned effectively at any time (this is my favorite theory for obvious reasons) and others have said certain times are better than others. When is the best time to prune, whether it is severe or moderate?

I have also seen conflicting information about the general growing cycles of jades. Am I correct to say that they are winter growers? Basically, I am looking for a definitive description of the growing cycle of jades, when to whack them, and when to root them.

Zach

Zach
cactusmcharris, interior BC Z4/5
15 years ago
I just likes to cut 'em.
puglvr1
15 years ago
Jeff, I'm also in your group "I just likes to cut 'em."

My personal reason behind "whacking" my Jades is simple, I like them small and more bonsai style(short and wide if possible)more treelike form is my favorite. So it is a personal choice for me...if the trunk gets thicker well...that's even better! They grow so slow for me anyway, I might as well keep them in small pots, easier for me to move them around during the wet and very humid rainy season in summer and the occasional frost we get.

Zachman, I can only comment from my own personal experience, but my Jades only grow and root best in late fall to early Spring, this is also the best time for me to do any "whacking". Once our temps starts to reach close to 80ÃÂ° consistently my Jades pretty much goes dormant. For me that's between April through mid November...my growth comes to a grinding halt. So you can see why my Jades grows SO slow, I have a very short growing season.

I do have to say that most of the time I've whacked my Jades, the trunk has gotten thicker. Coincidence?? I'm not sure, but I'm glad it does.
suc_gremlin
15 years ago
good thread ... im in the leave it alone group. i pruned my jade to the shape i wanted when i got it wich was single stem (it was a multi stem monstrosity) not touched the main stem i wanted and now im just going to wait. i may even 'experiment' with planting it in the ground for a season and see how much it thickens.
Denise
15 years ago
I can't attest to the logic behind it, but I just know that like Pug, the short stocky tree look appeals to me and whacking makes it so. My poor Crassula ovata 'Skinny Fingers' was beat up badly by a hail storm driven by 90 mph winds in June of '08, and here's what it looked like after I whacked off all the ugly...
{{gwi:623609}}

And this June it won a blue ribbon for Best Crassula AND a Best Monstrose ribbon...
{{gwi:584881}}

Denise in Omaha
greenman28 NorCal 7b/8a
15 years ago
Fantastic, Denise!
My 'Skinny' is starting to develop this nice form, as well.
So elegant and stately.

Josh
Denise
15 years ago
Thanks, Josh. 'Skinny' is the best for form for me. I've been working with both 'Gollum' and 'Hobbit', but they take a lot more talent to shape. 'SF' seems to naturally grow beautifully tree-like, thank goodness since I don't have the "eye" for shaping them that many of you do.

Denise in Omaha
puglvr1
15 years ago
Just beautiful Denise...that one you posted is one of my favorite Jades that you have! Congrats again on winning the "well deserved" blue ribbon!