Hard pruning to encourage growth?

Azaleas get very twiggy, and become brittle after a few years. As they age and become brittle, the cambium constricts at the twiggy new growth, and eventually causes the tree to weaken. Peter Warren talks about keeping trees “young” by hard-pruning them every few years.

I had let my kurume azalea grow for the last 10 years or so with very little hard-pruning and it started to decline. Look at this progression.

April 2017:

October 2017, after a full growing season, unpruned from the photo above. Look at the anemic growth:

March 2018 before pruning:

And April 2018, after hard-pruning:

It might be difficult to see how hard I pruned it back because the profile is still roughly the same. However, I removed about 1/3 of the ramification, back to secondary branches and leaving a few tertiary branches. The best way to compare is by looking at how much thicker the trunk appears in the photo just above from the one above with a few blooms opening.

A lot was removed, and I was a bit nervous as to how it would respond. Now look at the October 2018 shot:

This tree was last repotted in 2016, and sat on the same bench, same feed, same everything, with the exception of the pruning.

Below is a side-by-side comparison. Spring, no pruning on the left, pruned on the right:

And the after the resulting growing season, not pruned left, pruned right:

I did the heavy pruning just after I removed the fading flowers in April. Likely, I’ll do it again next spring.

The pot? 19″ wide Koyo, signed, stamped, and with the Fuji-en stamp. Dark clay, aqua glaze, with bamboo patterns on the rim and feet.

And here is a fall-color shot…really nice show this year.

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Spring work on a Kurume Azalea

Peak bloom was very nice this year. This Kurume produces three flowers per bud. Normally I remove 2 and leave one per bud, but that is time-consuming and this year I just didn’t get to it. It made for a very bright, but congested show. It also meant a lot of weight was hanging on each branch.

Time to remove the flowers, as they peak quickly and fade fast. The top and back shows they’re already beginning to wither. Once they wither, it makes their removal more challenging than when you can grab the flower and cut it off at the base, including everything down to the husk, leaving only last year’s leaves in place.

This tree is getting big, more than 32″ wide at this point. The pot is 19″. This is gonna take a while…

A time-lapse of the next 2 hours…

Time to clean up…

A few cool shots around the tree during the work:

Next steps are to get some of the weeds out of the soil. For some reason oxalis has moved in and wants to take over.

Also, probably time to deal with that rot in the back. All the punky wood was scraped out, and a couple drainage holes were drilled through, so water won’t collect. Then, a liberal coat or two of PC Petrifier was applied.

Next up, scraping away the top 1/2″ of the old soil, and replaces with fresh.

Peter Warren stated that azaleas tend to constrict themselves over time, and get old. Look at old azaleas and you can see that the twigs get very thin and it makes transport of water up and sugars down difficult, weakening the tree over time. It’s important to keep them young with hard pruning occasionally. So after a week of rest and heavy doses of organic feeding, the tree hopped into the barber chair for a haircut. Before:

After:

The tree was reduced by about 25%…or this much:

With some luck, the tree with bud back strongly and next year I can continue to replace old ramification with new, and rejuvenate the Bonsai.

Ben Oki Azalea bust

Sometimes things don’t work out.  This azalea has been reliable for a great show every April for the last 15 years.  This year, it was repotted into a nice Koyo pot, and I was looking forward to the new combination.  I didn’t do much root pruning, just new soil.  As of April 8, it seemed well on the way.


A few days later on April 13, still on track, but maybe a bit slow.  I chalked it up to repotting and a cool spring:


Then, it stalled out entirely.  I gave it another week, and by April 23, it was clear the crop of blooms had blasted:


So, it could be several problems; it dried out, froze, or maybe hit with a pesticide or fungicide.  I’m pretty careful to avoid spraying trees with chemicals while they’re blooming.  Checking the weather almanac, it didn’t freeze between 4/13 and 4/23, but it also didn’t rain.

Here is what I think caused it: I moved the azalea to keep the blooms out of the sun, and apparently the spot didn’t get good coverage by the irrigation system.  Hopefully losing the flowers for a year was the worst of it, and it will be a good growing season, but for now, here it is, cleaned up after the flowering bust.

By mid-May,the weak new growth was very yellow.


I’m thinking it could be one of three things:

1.  Lack of Nitrogen or Magnesium; or the ability to use what’s there.

2.  Fungal problem.

3.  Cumulative effects of 2 years in full sun.

I soaked the tree for a few hours in a solution of Eco-Vie.  I’ve been hitting everything almost weekly with Daconil, so I doubt it’s fungal.  But to be safe, I dunked the tree in a biological fungicide for a few hours to kill off anything that might be soilborne; maybe from the last tree I had in that Koyo pot.

The last option is to move the azalea into a whole lot of shade.  Which I did, in mid-July, as the heat index was hitting 106.  And while it was sitting in the shade, and I was sitting in the house searching the inter webs for other potential causes, I read where (duh) high soil pH presents as light colored leaves, or sections of the tree in azaleas.  So, I bought some soil acidifier and gave it a shot.

So after a month of feeding a soil-acidifying organic fertilizer, the color and turgor are a bit better, but still not impressive.  This is mid-August:

And 10 days later, the foliage color was improving, but the vigor has not.  The lower right branch is still rather yellow:


  I think I’ll remove the flower buds and keep piling on the acidic fertilizer and see how the next 6 months go.

At least it’s still sorta green!

And worst case scenario…ok, second-worst-case scenario, it could be an interesting single-trunk tree.  Hope we don’t get there though.