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Root pruning / repotting severely pot bound Acer Bloodgood
jamesharcourt
Posts: 465
in Plants
Last year I got a 6-7’ Japanese maple bloodgood which came in great condition but in a very small pot - I literally had to cut the plastic pot to get the plant out .... it was never coming out otherwise!
Attempts to loosen the rootball by hand were futile, it was like a rock. The roots obviously hit the side and started going back in on themselves multiple times.
Anyway I put it into a far bigger pot for the remainder of the season (without disturbing the roots) and it did ok - but was still a big lump of rock root sitting in compost.
Today, I took it out and some feeder roots had emerged about 3-4 inches in length but the immovable solid block of circling roots was still there - and I decided to "pot down" to a size where it wouldn't be sitting in potentially wet compost too long.
I didn't think sawing through it would be good as there were feeder roots inside the mass, instead I used a hose to try to loosen the rootball, coupled with a few goes at it with a claw. I ended up doing this for nearly 2 hours, pruning out one or two woody sections and generally pruning back the straggly stuff to produce something which was loosened up sufficiently to re-pot.
I went for a pot which was a little bigger than the original, but not too much bigger. I realised I had potted up too much and wanted to eliminate that problem. Picture below.
... the previous temporary "overpotted" pot earlier in the season:
The new pot is shorter but probably a tiny bit wider ... the previous pot was good for ratios visually but didn't allow much room for any root run out to the sides.
I don't have a picture of the one it arrived in but it was somewhere between 1/4 and 1/3rd the size of the black one above!
Has anybody else done anything similar, with any results good or bad?
Attempts to loosen the rootball by hand were futile, it was like a rock. The roots obviously hit the side and started going back in on themselves multiple times.
Anyway I put it into a far bigger pot for the remainder of the season (without disturbing the roots) and it did ok - but was still a big lump of rock root sitting in compost.
Today, I took it out and some feeder roots had emerged about 3-4 inches in length but the immovable solid block of circling roots was still there - and I decided to "pot down" to a size where it wouldn't be sitting in potentially wet compost too long.
I didn't think sawing through it would be good as there were feeder roots inside the mass, instead I used a hose to try to loosen the rootball, coupled with a few goes at it with a claw. I ended up doing this for nearly 2 hours, pruning out one or two woody sections and generally pruning back the straggly stuff to produce something which was loosened up sufficiently to re-pot.
I went for a pot which was a little bigger than the original, but not too much bigger. I realised I had potted up too much and wanted to eliminate that problem. Picture below.
... the previous temporary "overpotted" pot earlier in the season:
The new pot is shorter but probably a tiny bit wider ... the previous pot was good for ratios visually but didn't allow much room for any root run out to the sides.
I don't have a picture of the one it arrived in but it was somewhere between 1/4 and 1/3rd the size of the black one above!
Has anybody else done anything similar, with any results good or bad?
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The active parts of roots are the micro hairs which take up the water and nutrients and all this activity may well have dried them out or blasted them off which means it has to start again. Leave well alone apart form making sure it's fed and watered when thirty and hungry.
Thereafter, re-pot to a slightly bigger pot every couple of years until it gets to a maximum pot size for you and then keep it going with judicious feeding and watering and just refresh the top couple of inches/5cm of compost in spring.
I don't think I have dried them as the whole process was based around water and it was watered again when placed in the new pot.
It basically went from being massively under-potted to somewhat over-potted.
It is in an east facing spot so gets full sun until midday and then shade in the afternoon, which it seemed to like last year. It's near the house but the wind is hard to escape at my house, but it's not as exposed as some parts.
Last year I used maxi crop seaweed extract in the watering every fortnight and all the acers seemed to like that so I'm planning to use the same. Other than that I'll water normally at a maximum frequency of once-per-week ... maybe less if it has rained a lot, although the canopy and proximity to the house mean the rainwater doesn't always count for a huge amount unless it's a real long, steady rainfall.
We do this a lot with our bonsai acers etc!
But I’ve successfully rescued quite a few others from poor condition and for containers there are a list of key things, if you meet all of these you’re almost guaranteed success:
- free draining potting medium, ideally 50% composted fine pine bark, 40% normal compost and the rest perlite or pine bark mini mulch. Wash bad soil off if necessary. Oxygen to the roots is the most important thing.
- pot on the smaller side but not pot bound or girdling root, you want no less than 50% root mass in the pot, so soil to root ratio should by in favour of root
- proper drainage essential, so extra holes in the bottom of the pot - layers of gravel with one hole actually causes more sogginess at the bottom than 5 holes and no gravel
- raise the pot up on thick pot feet to ensure drainage and oxygen flow, I can’t repeat enough, oxygen exchange is key
- regular, even watering - e.g. 1 litre a day or every 2 days, whatever the weather ... right from the start of the growing season, the free draining mix and compact pot size will ensure you don’t over water and the regularity will keep oxygen exchange up for the root zone
- don’t keep moving it, the position it leafs out is the place it will be best acclimatised to
Still pains me that somebody just half-inched it from the driveway