Late summer

Hosta’s divide easily, you might have to tackle the big ones with a spade though

DIVIDING PERENNIALS

I don’t talk about perennial plants much. It’s not that I don’t like them, far from it; I think that they are a beautiful addition to any garden. It’s just that we don’t have many in our own garden. We have an Astilbe hiding in a very dry area underneath a conifer, which is probably about the worst place for it as they like very moist soil, and apart from a few herbs like lemon balm, we have a few large daisies that have been pot bound in a fish box by the shed for the last two years.

We have mainly shrubs in the garden with no herbaceous borders and very little bare soil, so that means no weeding. I bought two very good hoe’s from John and Mary in Malin at the beginning of the season and they are still in the shed with their wrappers on…. that’s the way I like it.

HERBACEOUS PERENNIALS
A friend of mine asked me to check out their perennial patch this week to seeabout giving it a facelift. The bed was planted about seven years ago and things are looking a bit tired.

Ideally, perennials should be lifted, divided and replanted every three to five years, so it’s time for some work to be done on their plants to keep them in good shape and colour. The rewards will be healthy, vigorous growth and a crop of new plants to expand their planting scheme. I can’t resist digging up some Jacob’s ladders and hosta’s to demonstrate the different kinds of roots….


WHY DIVIDE?
There are a few good reasons to divide your perennial plants:

· Clumps have started to die out in the middle. The classic “doughnut” shape with an empty hole in the centre is a sure sign that a perennial clump needs attention.
· Flowering performance has declined. The clump may have become congested, or the roots old and woody.
· Soil nutrients have been exhausted around the clump. Signs of this might be stunted growth, yellowish leaves or lack of bloom. Dividing and moving to a new location is a wise idea. Sometimes simply fertilizing the plant will make it smarten up.
· Perennial weeds like creeping buttercup or grass have infested the clumps. When this happens, usually the best approach is to dig up the entire clump and divide it, picking out every single piece of weed root that can be found.

Dividing established clumps can provide plenty of new plants for a new garden bed, or to share with friends and neighbours.


When to divide
Plants should be divided when they're dormant, in late autumn or early spring. Fleshy-rooted perennials, such as peonies, should be left until the end of their dormant season in late spring, before being divided. Their buds will begin to shoot, which will indicate the more vigorous areas of growth, and therefore the best way of dividing up the plant.


How to divide

· Lift the plant by loosening the surrounding soil, taking care not to damage the root system.
· Once lifted, shake off as much loose soil around the roots as possible and remove any dead leaves and stems with secatuers.
· Make sure all buds are visible before dividing.


Fibrous-rooted plants

· Place two hand forks back-to-back near the middle of the plant.
· Gently push the handles back and forth so that the prongs gradually tease the plant apart.
· Repeat the process with each portion to divide the plant into more sections, making sure each section has a healthy bud.
· Discard the old, woody growth from the centre of the plant.
· Some fibrous-rooted perennials, such as primula, form a loose crown of many stems so they can be pulled apart by hand without damaging the plant. You can also take off separate stems growing at the edge of the plant, just make sure each portion has its own roots.

The fibrous roots of the Jacob’s Ladder divide easily. Try not to get too carried away though as you could get hundreds of divisions.

Some common fibrous rooted plants include: Artemisia, Asters, Aquilegia, Golden Rod, Herbaceous Campanulas, Forget-me-not Herbaceous Geraniums, Meadowsweet, Perennial Spiraea, Perennial Sunflowers, Primroses and Yarrow.



Fleshy-rooted plants
Dig up the plant and with a sharp knife separate the woody crowns.

· Make sure that each new piece has strong roots and several bud growths.
· Plants with fleshy roots can be divided with a spade.
· Make sure the new shoots are visible before dividing.
· Trim each division with a knife, discarding any old, woody material and damaged growth.

Again if it’s an old big clump that's been in the ground for several years or more then throw away the centre part. Plants with fleshy Crowns include: Delphiniums, Lupins, Astilbe and Hosta.


Dividing rhizomes.
· Dig up and select young outer pieces.
· Use a sharp knife to separate the rhizomes.
· Select pieces that have at least one or two fans of leaves from the outside of the clump and discard the centre rhizomes.


Plants with rhizome roots include: Flag Iris, Lily of the valley and Orris Root.


Replanting
After the plants have been dug and divided there are a few steps that will need to be taken:

· Replant divisions as soon as possible, making sure that the roots don’t dry out. In general, divisions should be planted at the same depth as the original plant, leaving enough space between plants to develop.
· Ensure that roots are evenly spread out in the planting hole before gently firming the plant in.
· Add soil improvers such as well rotted manure or rich compost into the planting places.
· Water the base of each division immediately after planting, and keep the plants well watered while they settle in.


There are a few perennials that don’t respond well to being divided which include: Alyssums Candytuft Carnation, Delphinium, Euphorbia Foxgloves, Geraniums, Lavenders and the perennial Sweet pea amongst others.

Once you start to divide plants, you will get a feel for those that will do well when divided.