Divide and re-plant to give your garden a spring makeover

Things are starting to grow at last and some of the herbaceous perennial plants such as golden rod, phloxand hostas are emerging from the soil.

Friday, 22nd March 2019, 5:00 pm
Updated Friday, 22nd March 2019, 5:01 pm
Re-planting your perennial plants is an essential job to be completed at this time of year.

This is a good time to divide plants because if they have been left in the same spot for more than three years, the flower stems become overcrowded resulting in the flowers losing their glamour and colour. This happens because the plant has used minerals in the soil but we can rectify this by lifting out the clumps, dividing them and replanting straight away.

This operation calls for a pleasant day fairly soon and the whole of the month of March is the ideal time.

Start by removing a few clumps of soil and set them aside to allow for the area to be dug over to the full depth of a garden fork. Break down the soil and add five inches of well-rotted manure to the top of the soil. 

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Once dug over, the soil should begin to dry fairly quickly. If it’s very heavy or like clay, apply two/three inches of sharp sand and work this into the top four inches of the soil. This is the cheapest way of improving heavy soils.

The clumps which were dug out and set aside can now be divided. Small plants such as hardy geraniums can be split up using your hands. But ensure each section has plenty of roots before splitting it which may make three plants out of the original one. 

Larger plants, such as golden rod, are much more difficult to divide by hand. However an easy method, used by professionals, is to use two garden forks. One is thrust into the centre of the clump and the other alongside, back to back. The handles are pushed together and the clump them divides. The ideal size of a clump to be replanted is about six to nine inches across.

Choose the outer part of the clump with shoots because the middle of the clump is often dead or poor quality. Once divided, it is very easy to remove white underground stems of bindweed, couch grass, ground elder and horse tail – all of which are difficult to eradicate in herbaceous borders.

In large herbaceous borders, replant the divided plants in threes or fives because it ensures a good impact of flowers and allows the border to be designed to make best use of colour. It is likely that only one plant will be needed so donate the others.

The plants are now ready. Scatter four ounces of Vitax Q4 fertiliser per square yard and work into the top few inches of the soil. All this forking over is going to make the planting a lot easier to do so it is worthwhile.

It’s important to support the plants by using sprays of hazel around the outside of the plants. It may not look very pleasing but the foliage quickly hides the hazel sprays. They still use this method at Kew, Ventnor and Wisley gardens.

To finish the job, the soil is forked yet again so that all compact areas are broken up and all signs of footprints have vanished.

It’s another job done and if you are wondering – yes, I am doing this job in our garden at home and I reckon it will take a week to complete!


This week’s top tip: 

If you are short of space in the greenhouse, find shelf brackets at the garden centre which will slot into the upright glazing bars of the greenhouse. It’s cheaper to buy wooden shelves as metal shelves are expensive.