Friday 20 September 2019

In the Garden: Division breathes life into old plots

This is a good time of year to lift, divide and re-plant perennial flowers, writes Gerry Daly

While there has been something of an increase in the popularity of shrubs in recent years, perennial, non-woody flowers still suit modern gardens
While there has been something of an increase in the popularity of shrubs in recent years, perennial, non-woody flowers still suit modern gardens

Gerry Daly

While there has been something of an increase in the popularity of shrubs in recent years, perennial, non-woody flowers still suit modern gardens. Shrubs have made a comeback with compact varieties and shrubs form a woody backbone to a garden, but it is largely the non-woody plants that provide flower colour in masses.

Perennial flowers are quick-growing and can cover ground rapidly, denying it to weeds. Most of them die-back in winter, bar some evergreen types like phormium and libertia. But while they are limited as to height - the same year after year - some kinds spread outwards to new, unclaimed territory.

A problem about using perennial flowers to any extent is the need for many more plants to fill the same area that a few shrubs might easily fill. This is especially the case with larger gardens. However, a plant's need to expand and the garden owner's need to fill space and keep weeds at bay can suit each other.

It is often recommended commercially that perennial flowers are planted at five plants per square metre to fill space quickly, but, for domestic purposes, two or three is usually plenty. It can be expensive to purchase enough plants to plant up any sizeable area.

Arthur Shackleton
Arthur Shackleton

The way around this problem is to purchase a few plants and divide them. Sometimes, large well-grown garden centre plants can be taken out of the pot and split before they are planted. More often, the plants will have to be grown in their new site for a year or more before they are large enough to divide into three or more sections.

When buying plants, have an eye for their size. Quite often, plants that have been too long in a pot, and look as though they are past it, can recover amazingly well when divided and planted in good soil.

This is a good time of year to lift, divide and re-plant perennial flowers. It can be done at any time of year really, watering until new growth is made in summer, and less often, or at all, in the cooler wetter half of the year. Most kinds are not now fully in active growth, scaling back before winter. When divided in autumn, they make some new root growth before going dormant for about four weeks from mid-December, and they will be nicely settled in before the new season growth begins in early spring.

To divide a plant, simply lift it with a digging fork, loosening it all round to start with. When lifted, shake off some of the soil or tap it on the ground. Many kinds can literally be pulled apart to give a handful of roots to re-plant. Others are tough and may need to be cut with an old knife, or even chopped up with a spade. The well-worn advice to use two digging forks back-to-back to prise the clump apart does work, but who has two digging forks these days? Nor does it give better results in terms of survival and success.

As a general rule of thumb, lift and divide spring flower types in autumn while they have time to settle, and summer-flowering kinds can mostly be divided in winter when dormant. An important exception to dividing perennial flowers in the autumn is grasses, most of these resent being moved in autumn and should be left until spring.

The divisions should be replanted into weed-free ground immediately and given a watering to settle them in. The soil can be improved before planting by spreading and digging in well-rotted manure or other organic material. This will feed plants for a few weeks.

And, remember, although division is a good way to get new plants, it is also a good way to rejuvenate perennial flowers that have grown old, swamped by other flowers or shaded if they are not shade-lovers. If they are not flowering well, the old plants should be dug up and some parts of the more vigorous growth retained for re-planting. If you have too many pieces left after dividing old flowers, you can always give them away.

LAST CHANCE

Created 10 years ago by garden designer Arthur Shackleton, Fruitlawn Garden just outside Abbeyleix, Co Laois, is a one-acre garden within a walled setting. Its final open day of the year is on Sunday, September 15, with unusual plants for sale from 10am to 5pm. Tickets €5. Children under 12 go free. Visit arthurshackleton.com for more details.

SOUND OF MUSIC

A musical treat for gardeners comes to the National Botanic Gardens, when the ConTempo Quartet returns with a contrasted repertoire featuring Johannes Brahms's lyrical and tumultuous quartet No.2 in A minor and Fanny Mendelssohn's melancholic and daring quartet in E major, on Sunday, September 15, 3.30pm, Tickets, €15, from contempoatthegardens.eventbrite.ie

PERENNIAL FAVOURITE

A favourite date in the plant lover's diary is here - the autumn plant sale at St Brigid's Parish Centre in Stillorgan kicks off from 10.30am to 1pm on Saturday next, September 14, and promises lots of favourites as well as some choice rarities.

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