Thursday, 15 February 2018

Time to cut back perennial plants

Dead seedheads on Sedum spectabile Green Fingered Blog
When is the right time to cut back herbaceous perennials in the garden? When you see fresh new stems growing from the base. In my garden that means now - go and have a look at yours - it's time to let spring take over from winter...



There are various things that signal the onset of spring in the garden, but if you need convincing, here's what to do:

1. Go outside to your garden.
2. Find a perennial plant (like the Sedum in the top picture).
3. Look at the base of it.

Time to cut back herbaceous perennials


Herbaceous perennials are so called because they come back into growth every year after dying off at the end of the previous growing season. Some wither and fade by themselves each autumn. Some will get blown apart by autumn winds, others disintegrate in January ice. 

Others have stems and flowerheads robust and woody enough to withstand the worst of winter and last right through to spring.

Some of them have an interesting or attractive enough appearance to be worth leaving them there over the winter. Although dead, they provide some structure when everything around them has shrunk back into the ground. They can look beautiful on frosty mornings when covered in icy crystals, and they add texture to an otherwise potentially bland wintry scene. It can also provide food and shelter for wildlife.

So you had an excuse for not tidying the garden for winter, but you can't put it off much longer. It's time to cut them back.

If you look closely underneath them now, you'll probably see something like this: 
Fresh shoots on Acanthus spinosus Green Fingered Blog
Acanthus spinosus

You'll see shoots emerging from the base of the plant, and this means these seed heads and stems have done their job of giving you something to look at in winter. It's time to move on.

Now's the time to remove the remnants of last year and start looking forward to everything the garden has in store for you this year. 

Just cut the old stems right back to the ground and enjoy the fresh bright growth left behind as it takes over, giving hope for the coming year as the garden gets going again.

Take the Sedum spectabile at the top of this post. It was still standing nicely upright after a wet and windy winter in my garden. Here it is a few minutes later after I removed all the seedheads and stems. The new growth has barely broken the ground up to now, but it will soon get going now that Spring is just around the corner.
New growth on sedum spectabile Cutting back Perennials Green Fingered Blog
Sedum spectabile


Verbena bonariensis seeds itself freely around my garden and new seedlings each year is pretty much a given. It's technically a biennial, meaning in it's second year it flowers, sets seed and dies. In fact, some of them survive the winter and start growing again from the base the next spring. 

By February the tall spindly stems no longer look as attractive having been buffeted by winter storms.
Verbena bonariensis stems in late winter Green Fingered Blog
Verbena bonariensis stems in late winter...

But they're not put off easily.  Despite being a biennial plant, they sometimes behave as perennials and produce new growth from the ground. Below you can see two remaining old stems: in the centre and to the left, and two new green ones.


New growth on verbena bonariensis Green Fingered Blog
...with fresh growth at the base before pruning...

Unless the tall stems get blown over, I leave them to shed their seed and look interesting through winter, but once I notice them regrowing, I cut them back to the base, taking away the tall stems and leaving the fresh growth to start again. 

Cut the dead ones away and you're left with the emerging shoots ready to grow straight up. These will produce pinkish purple flowers at head height in summer. 


New growth on verbena bonariensis Green Fingered Blog
...and after pruning

Sometimes the growth on verbena will start appearing halfway up, or part way along the stems, particularly if they have by now been blown horizontal and are lying down. If they are left to grow from this point they will just be too tall and fall over, but the growth at the base is a great start to have before the seedlings appear.

With loads of brand new seedlings as well, I end up with a soft purple haze across the border.

This cutting back process can be applied to anything that's regrowing in this way. 


GREEN FINGERS TIP
Some grasses are herbaceous too, but be sure to check which type you have. If it's herbaceous, then cut it back to encourage fresh growth (you might not see any until you do). But if it's an evergreen grass, don't cut it back - comb out the dead leaves from last year instead.



Lupins are perennials and as you can see, mine are pushing up their distinctive leaves now. So any remaining dead stems from last year should now be taken out, clearing the way for them to flourish and expand.
Fresh growth lupin Cutting back perennials Green Fingered Blog
Lupins appearing from a winter below ground
  
So off you go. I know it's cold, but get out in the garden and see what's growing. Start to cut back the remains of last year and give spring room to grow.



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