NZ Gardener

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Have you heard of the Chelsea chop?

This pruning method takes its name from the Chelsea Flower Show as, in the northern hemisphere, it is usually done in May, coinciding with the annual event. Here in the southern hemisphere, this is the time it can be done on the perennials which can become unruly in summer.

Sedums, I find, can flop over other plants, so when the new growth is about 6cm I nip out the centre growth tip, then in a few weeks many side shoots appear which makes the plant really compact and bushy, so it then needs little or no tying for the rest of the summer. This can also be done with phlox and monardia, and many other perennials. The flowering season will be a little later and the flowers are sometimes a little smaller, but you get more flowering heads.

Mulching this time of the year is a must.

Clean out your compost bins and put a good layer over the whole garden as this not only feeds the plants but keeps the roots cool over the hot summer months to come. Plus it makes the garden look good and helps suppress weeds.

Most perennials are surface rooting, so a little artificial fertiliser covered with compost will work wonders.

If growing perennials in pots, repot into a good potting mix which has slow release fertiliser and water retention crystals, and you will be well rewarded. I see so many perennials in pots which have never been fed or repotted, and the owner wonders why they are not performing.

This is the month when dahlias and delphinium­s emerge, and you need to be vigilant, watching for those dreaded slugs and snails which love to eat the new foliage. Get out the slug bait or get your beer traps out to kill these nasties.

Shifting perennials this time of the year is fine provided you take plenty of soil with the plant. Often I water the plant the day before and this helps hold the soil together better. When planted, make sure you water the plant well and keep it damp but not too wet for about a week. If you get really hot days, perhaps put a little shade cloth over the plant for about a week – this helps transpirat­ion.

Some of the taller perennials may need the first string around them before the winds arrive.

I don’t like using synthetic string as it not only looks awful, it cuts into the soft upright shoots when the stems rub onto it. I use a soft, natural fawn-coloured string and find it is not easily seen and more eco-friendly to use.

A friend of mine saves her string for another season and then when you have a cleanup the following year, you can put both string and tops into the compost bin (but not if you have used synthetic string).

Don’t be put off by negativity towards perennials. They are not a lot of work and you will always be well rewarded for your efforts, with plants looking good and lasting for over eight months.

 ??  ?? ‘Souvenir de la Malmaison’.
‘Souvenir de la Malmaison’.
 ??  ?? Paeonies and iris at Trotts Gardens.
Paeonies and iris at Trotts Gardens.
 ??  ?? Delphinium.
Delphinium.
 ??  ?? Rodgersia ‘Big Mama’.
Rodgersia ‘Big Mama’.
 ??  ?? Iris ‘In Town’.
Iris ‘In Town’.
 ??  ?? Hosta ‘Great Expectatio­ns’.
Hosta ‘Great Expectatio­ns’.
 ??  ?? New growth of Polygonatu­m ‘Variegatum’.
New growth of Polygonatu­m ‘Variegatum’.

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