More plants for free

WHAT can beat getting plants for free? Over the next three weeks I’ll look at different ways of doing this with herbaceous perennials. Starting this week, I’ll explore dividing, next week taking cuttings and finally collecting seed.

Not only do you get more of your favourite plants, but some give you better results through division. A clump of bearded iris dies in the middle, flowering round the perimeter, so you rejuvenate by discarding the centre after lifting. And Anthemis tinctora often fades and performs poorly after three or four years.

Divide most clump-forming perennials, either in autumn or spring. Although spring flowering plants should be divided just after flowering, September’s the time for the later ones, especially if you’re replanting in a border.

This lets the tubers or rhizomes put on some growth before winter. If you’re potting up after dividing and then planting out in spring, you can delay dividing until October or November.

Use a fork, not a spade, for lifting as this will cause less disturbance to roots, working patiently round the perimeter and gently ease the crown up, brushing off any loose soil.

You should keep the roots moist from the outset and continue by keeping the growing plants well watered. Then soak the lifted clump, either in a bucket or with a hose. My burn does the job beautifully!

Some perennials are easy to separate. With ajugas, simply tease apart all the plantlets that make up the clump. Small fibrous rooted heucheras and hostas are also easy to pull apart.

But the large crowns of greatly underrated hemerocallis take more work. Drive two forks, back to back, into the centre of the clump and use them as levers to prise it in half. Repeat until you’ve got the number of plants you want.

It’s beyond me why hemerocallis – daylilies – aren’t much more popular. Their commonly used name describes individual flowers that only last a day, but people don’t always realise that individual plants carry a mass of blooms that open over a long period. For subtlety and elegance, these captivating flowers are unbeatable.

The genus originates in China and the Far East, but many of the 80,000-odd cultivars were developed in the US. I saw what must be one of the finest collections at the Jardins du Chateau de Vullierens in Switzerland a few years ago. I could see how the 200-odd cultivars on show varied in height, from 15 to 150cm,