Perovskia "Blue Spire."

Colour now fading and it is going to seed. Wondering what to do re the stalks. In the past it has taken care of its self but it has grown impressively and I want to take care to attend to it in the best possible way. Any thoughts?

 

SimonZ......not too complicated. Wait until spring and then prune to a few inches of the ground if you want a more bushy plant...as I do....or to a little higher. (Stems will be less lax too if you cut harder) Cut to where lowest new shoots are growing; you can see then which stems are dead so so remove these entirely.

 

Hi, this plant is now putting out new green growth. I am wanting to clarify what I should do next. I began cutting to the new shoots today, but note you also say above it is possible to cut to within a few inches of ground. Presumably if I do so, new growth will still come this year. I'm tempted to cut some of the plant right back but keep some of the new growth.

 

Hi @SimonZ , if it was mine I would cut the old stems between the new shoots, for instance in pic 1 just above those two shoots.

 

Hiya SimonZ
Yes you can right down to the ground now. This helps make for more sturdy growth disinclined to flop. I would cut all growth back to the ground but if you prefer to you can prune to where the new shoots appear.
It will still grow and flower whatever you do

 

Update: I cut back down to the ground as suggested. The plant flowered moderately through the summer, a bit shorter than usual but somewhat bushier. It was quite battered by the rain and the front half or so of the clump became quite bowed forward at one point. But even the combination of quite heavy sun and very heavy rain did not result in a vigorous growth. I'm wondering ifanyone has any tips as we go into the autumn? Thanks.

 

What is your soil type, Simon? Perhaps an important factor here. Asking because I absolutely love these and want to block/drift plant them both on my allotment and at home.

Nick

 

Yes SimonZ
Do nothing until the spring now......then prune back to a few buds. If you want it to be a little sturdier, less floppy, then you can cut again around early May.
Don’t feed or water too much, if at all, next summer. Grow it hard
It is a fairly hardy plant

 

Thank you for everyone's input on the above. I'm amazed its a year since my original question, and am now back to the flowerless stems and assuming I should proceed as before, ie wait until spring before cutting anything back?

 

Apologies for not replying Nick, I must have missed this. Its an acidic soil and quite stony - I live in the Calder Valley, Yorks, in a very wet environment, heavy rains and quite high up so winters can be very cold and windy (as can the rest of the year to be honest!)

 

Perhaps this article will help. Seems our friend Verdun's advice to prune in early May was spot on for your region, Simon. I planted three in my back garden in Summer but am a tad concerned about them not performing well after reading this because my site doesn't get year-round sunshine! I'm not brave enough to cut them right down this Spring but may do in future years.

"In addition to a site with year-round sunshine, success with perovskia is all about pruning. In our climate the plants come late into leaf. They should be hard-pruned back to a little woody framework, no more than a few inches tall, just as they are beginning to leaf up. This will probably not be until mid-April.

If plants are pruned too early and too hard they may simply give up and die. If in doubt, it is best to wait until May when they will be in full growth. However, if perovskia is not pruned hard enough the growth can become lax and floppy, particularly when the plants are young. The untidy mess that ensues, while still attractive in a wild and woolly way, does not show the plant off to its best advantage and the flower spikes may get swamped by neighbouring plants."

How to grow: perovskia

Nick

 

Just wondering now whether to stake/tie back this perovskia? It is coming into flower, but some stalks are not flowering, and are very bowed over, due no doubt to a combination of recent excessive rains, and its own heavy weight now that the plant has multiplied. I confess I didn't adhere to the advice above and cut back in May this time - other things in life took over a bit this spring, as I'm sure can be imagined in the current circumstances!

 

While this plant grew and spread nicely across the front of the garden, one clump seemed top get bowed down by heavy rain, and inexplicably flattened at the base under a rock. I've removed the rock, and placed it as a support in front of the stalks, and am wondering if the clump will revive.