Pruning Penstemon

[bend1pa]

I have a Penstemon Pensham variety which I have not cut back yet. The old stems and leaves turned out to be evergreen and look healthy and are starting to grow again.

I was wondering whether these should be retained or pruned right back to the crown now?

[WendyC]

I would prunings back leaving 2 or 3 buds on each stem. If the top bud fails you have a bit of insurance in the lower buds.

[Martin H]

I've found that Penstemons need to be treated more like a shrub than a herbaceous plant. My regime is to shorten the stems in late autumn so that they are about half to two thirds their previous length. This helps protect the crown from the worst of the winter weather; the plants aren't reliably hardy every year. Then in April once they are putting on growth, cut them down to strong shoots near the base, removing any dead bits at the same time. I did mine this week. A bit of a feed would be worthwhile too, I must do that.

If you don't cut them back they get leggy and woody and unattractive.

Last Autumn I took some cuttings as a precaution, most of them have come through fine so now I have too many Penstemons again. Some of them will go down the allotment for the bees to find.

[bend1pa]

Thanks for the replies. Interesting that you suggest treating Penstemons as shrubs. Anyway I'll cut them down to new basal growth.

[Valleyman]

My penstemons are evergreen aswell.

I can't say i give them much care or thought. I just stick my hand in them to check for new green growth coming from the middle and then clip them right back to that every year. I do it around this time every year.

[bend1pa]

Well, miy Pensham penstemons are flowering ok now if a bit later than I expected. I noticed by late June in garden centres that I visited that similar penstemons for sale were already starting to flower.

[*wallflower*]

Really helpful thread! I have never been sure how to deal with my penstemon so will certainly try pruning it back as suggested.

Mine seems to be finishing flowering now, is it worth deadheading? Will they try and put on another lot of flowers?

[Martin H]

If you dead-head, snapping off the flowered shoot back to where there are new shoots or buds in the leaf axils, they will flower again. You can keep them going to the frosts if you're diligent.