Confused by my Verbena

Hi to you all

I planted 3 verbena bonariensis last year and they were great - blooming on and on and loved by the bees and butterflies.

When it came to winter I took down some advice from somewhere saying "Protect the roots with a layer of straw or mulch in winter, and don't cut back the dead stalks until new ones have emerged in spring".

So I've been waiting for new stalks to emerge from the mulch to allow me to cut back the old dead ones. But some of the old "dead" ones seem to be going through a rebirth, with previously dead stalks coming back to life from the bottom up and leaves sprouting out along them. Are all of the stalks going to do this and should I delete the advice I'd noted previously? Or will only a few do this and the rest need cutting back?

Thanks for any advice and insight into what is going on and what will happen next

Gavin.

 

Hi Gavin, I love Verbena Bonariensis.

The advice you took was good. V. bonariensis is pretty hardy but not always 100%. So the idea of a straw mulch was to protect the roots from frost, giving it a better chance of surviving the winter.

Like many other garden plants, its a herbaceous perennial - albeit short lived. That means that all the growth above ground dies back over winter and the plant survives as a root system under the ground. In the spring it will start to grow again from the roots. So at some point you need cut back all the old growth. Sometimes old stalks may not have been killed off in a mild winter and they will start growing, but its probably better to cut them off anyway - just leaving the new growth from low down.

There is a debate, that we have had on this forum, as to when to cut them back. Generally if you live in the south you can cut them back in autumn. But if you live in the north where its colder, a lot of people will leave the dead top growth on over the winter and cut them back in spring. The reason is that the top growth, and this applies to all plants, tends to give a bit of extra winter protection - a bit like a fleece. And this increases their chance of surviving the winter.

I live in Yorkshire, which is cold. So I leave the top growth on over the winter, but I don't bother with the straw mulch, as my Verbena usually survive without it. But even if your Verbena dies, don't give up hope. Its a prolific self seeder and you will find loads of seedlings all over the garden.

 

Mild ish winter and they will survive without any protection. They also shoot from the base and from the old stems. I tend to ignore them, no extra coddling and cut them down in the general tidy up in either Autumn or Spring, whenever I get round to them. they have survived this treatment for the last 16 years.

 

Many thanks for your feedback PeterS and Palustris. So next year being near Oxford in the South I should cut back early.

What do you think I should do this year, given where things are now? Let things just carry on as they are or cut back the stalks that haven't started growing yet?

Gavin.

 

I would cut back all stalks to close to ground level, obviously leaving any new growth from a low level. In that respect its the same treatment I would give to most other perennials.

 

Many thanks PeterS - I'll put this into action at the weekend

 

I leave 9" to 12" when I cut back - so I know where the blighters are when I am weeding in the Spring and the new growth hasn't yet peeped through!

I think Oxford has cold Winters, albeit "down South"?? Personally I think cutting down herbaceous stems has more to do with how tidy you like your garden to look in the winter. As an alternative you can cut them to a "tidy" length in the Autumn, and then shorter in the Spring. If you are going to put some straw on for protection I would leave some stalks to help anchor the straw in place.