Blog: Don’t you love getting something for nothing?
This is the perfect time to be dividing perennial plants to increase your stocks, fill any gaps in your garden or give spares away to friends.
The soil has started to warm up, and herbaceous perennials are waking up and putting on new growth. Just to clarify, I’m talking about plants here that die down every winter and sprout again in spring with generally soft, leafy growth. This doesn’t apply to woody shrubs. Read about the plants I divided to fill my new raised bed.
If you’re in any doubt, the plant you want to divide should have a crown. For a successful division, each bit of the new plant should have a clump of roots and stems. This year, I chose to divide:
- Aster Barbados (Island Series): Very late-flowering dwarf lilac/purple Michaelmas daisy with yellow centres – vigorous!
- Rudbeckia Goldsturm: Classic late summer deep yellow daisies with dark brown/black centres. Shaded out by the Asters.
- Astrantia Buckland: Long-flowering white/pink/greenish masterwort.
- Heuchera Marmalade: Classic variety, pink/caramel leaves, sorely in need of renovation.
Why divide herbaceous perennials?
It’s best practice to divide perennials every three years or so. As the plants grow, they spread out from the centre of the crown, often leaving a ‘dead’ patch in the middle. Plants often lose vigour, too, and this leaves them at risk of disease or pest attack. Dividing them creates young, healthy plants which are clones of their parents.
Dividing perennial plants – How to do it
With a garden fork, gently loosen the plant working outwards from the crown. Place it on a flat surface. Some people push two forks back-to-back into a large plant’s crown to prise it into two pieces, or however many you want.
However, with weak wrists, I find dividing perennial plants this way very difficult. I have these after a fight while dividing an ornamental rhubarb a few years back. The rhubarb won, and I ended up with torn ligaments! For bigger plants or those with woody crowns, I find it’s best to cut them with a pruning saw. This gives me control and a bit of power. You can also use a sharp spade (although that’s how I hurt my wrists), half-moon lawn edger, gardening knife – even an axe!
Here’s how my plants were dealt with:
Aster Barbados
Coming from just three small plants bought less than three years ago, these have really grown well. Too well, as they completely shaded out the Rudbeckia they were bought to go with. From those plants, I ended up with 14 well-sized plants with plenty of shoots and a good root system. The pruning saw worked well here.
Dividing perennial plants – Rudbeckia Goldsturm
A different approach was needed here. There was new, but poor, growth after so much unintended shade. I gently teased out what were basically 11 plantlets and put them in pots. They’re too small to go into the garden yet and are growing on the black wall in full sun. In a couple of months, I’ll plant them in their permanent positions.
Astrantia Buckland
After only a couple of years, these Astrantias have bulked up nicely and flowered beautifully in a semi-shady spot by the pond. if only I hadn’t planted them in a line! I resolved to make that better by dividing them – three plants yielded nine new ones. Now five of them are planted around an Astilboides tabularis (shieldleaf Rodgersia) bought in a plant sale at The Alnwick Garden last autumn.
Dividing perennial plants – Heuchera Marmalade
Frankly, these were a mess and had been in the ground for far too long. Heucheras tend to lose their lower leaves after winter and ‘ride out’ of the ground, looking leggy. I dug up several plants, split them by hand into little plantlets and replanted them in gritty soil to help them root more easily. They’ll get to a point when I can move them on again as they grow.
The extra Astrantia and Asters have ended up in the tropical bed – not very tropical, but the bare soil was driving me mad, and beggars can’t be choosers.
Looking after plant divisions
It’s important to get divisions into their new homes as soon as possible. Take the chance to enrich the soil with some organic matter or slow-release fertiliser. Water plants in well. Be water savvy – soaking a couple of times a week in warm weather is far better than a dribble every day. It encourages deep rooting, where the plant can find its own water supply. Deadhead spent flowers and keep feeding throughout the growing season.
