Hello all

Can anyone give me advice on what to do with a very old Potentilla bush.
It must be a good 30 years old. It flowers every year prolifically with
primrose yellow flowers, and we're very fond of it.

HOWEVER, year by year, inch by inch, it has got too big, and too
scraggy. I need to lower its height, and preferably improve its
bushiness. I definitely don't want to take it to ground level, unless
that is the advice from this group!

Here are two pictures:

http://tinypic.com/r/2eghg75/7

http://tinypic.com/r/67plsg/7

It's now about 5 feet high -- we'd prefer it to be about four feet. I've
always been reluctant to prune savagely because I'm afraid it won't come
back. However this summer it had to have some branches removed because
of flower-bed -redesign, hence now would be a good time to have a real
go at it.

TIA for any advice
John

I've never let mine get leggy, so I'm not sure whether you can encourage them to bush out lower down by hacking them back. But certainly in relation to the general thatch at the top I hack mine back pretty hard from time to time and it continues to thrive. Though I have noticed that a smaller-leaf red-flowered one is less vigorous, and can take a couple of years to recover from a hard hacking back.

On 02/11/2010 12:36, Another John wrote:
Hello all

Can anyone give me advice on what to do with a very old Potentilla bush.
It must be a good 30 years old. It flowers every year prolifically with
primrose yellow flowers, and we're very fond of it.

HOWEVER, year by year, inch by inch, it has got too big, and too
scraggy. I need to lower its height, and preferably improve its
bushiness. I definitely don't want to take it to ground level, unless
that is the advice from this group!

Here are two pictures:

http://tinypic.com/r/2eghg75/7

http://tinypic.com/r/67plsg/7

It's now about 5 feet high -- we'd prefer it to be about four feet. I've
always been reluctant to prune savagely because I'm afraid it won't come
back. However this summer it had to have some branches removed because
of flower-bed -redesign, hence now would be a good time to have a real
go at it.

TIA for any advice
John


Hi John,

I used to have a 25' hedge of this Potentilla, so I've done quite a lot
of pruning with it. It generally copes well with pruning due to its
vigour - it's not called Potent-illa for nothing :~). However, because
yours is quite old now, I would be slightly cautious; older plants can
die from the severe shock of really radical pruning for the first time.

Because you want a finished height of 4', I suggest you cut it back to
about 3' now. Then stand back and look at the older woody stems. Take
out about 1/4 of the oldest wood. IIRC, these are greyer and shaggier
(with their peeling bark) than the rest. Because you don't want to lose
this plant, I would stop at that until you see new green shoots
sprouting in spring. When you see this growth, you can then choose to
cut back further to this strong, green growth if you want to improve
further on its shape.. Having got the height and shape you want,
scatter some general fertiliser around the root area of the plant.
Using a fork, lightly prick over the soil to break up any compaction
(and to help the fertiliser to penetrate), then give the plant a good
watering. Over the next three years, you can cut out another 1/4 of the
old wood each year until none of the existing old wood is present. At
that point, you will have completely rejuvenated your shrub. Hopefully,
it will then bloom for many more years.

--
Spider
from high ground in SE London
gardening on clay

Hi Another John, certainly it needs pruning and with so much of the growth on the 'top' I think from personal experience you have two options :-
option 1--- for this, timing is critical, prune everything by about 1/3 just as it comes into leaf in the spring. By doing it at this time of year when there is that surge of growth, I find, even stems that wouldnt 'break' at other times will throw shoots.
option 2--- at the same time of year, bud burst in the spring, prune half to threequarters of the bush, leaving the remainder as sap drawers, when the pruned branches have new shoots, you can then chop of the remaining few.
This way takes longer but mave prove more successful, especially if the branches your cutting are paerticularly old as they appear to be.
Either way, if your really lucky, you may get lots of shoots from lower down straight away, in this case you could even cut the stems lower again, thus regenerating the bush from lower down. You might find the subsequent growth is strong, straight and like what we call 'watershoot', if this is the case you again have 2 options:- firstly, when the new growth is about 8 ins long, pinch out the tips to encourage bushiness, or, prune all the new growth by 1/3 in the first week of August, pruning anything at this time of year will have the effect of producing a naturally bushy, compact habit.
hope this helps, best wishes Lannerman

Hi all

Thanks for the advice proffered for pruning the potentilla, seen at:

http://tinypic.com/view.php?pic=2eghg75&s=7

I'll now wait until Spring, and then combine the advice from lannerman
and echinosum, which looks eminently sound: thanks a lot!

John