March Clumber Gardener

Chris Margrave Head Gardener

We caught up with our Head Gardener Chris Margrave to find out what's happening in the Walled Kitchen Garden this month and what you need to be doing in your gardens for the season ahead.

Mulching would come high in the top ten of labour saving techniques for busy gardeners.  It is worth doing on all soils, be they heavy clay or light sand.  It simply involves spreading a layer of material over the surface of the soil, mainly to help keep weeds in check and retain moisture in the soil, a particular benefit on Clumber’s sandy soil.  Mulches can also protect the roots of plants in cold winter weather and can produce a decorative appearance to the soil surface.  Several materials are suitable.  I have seen seaweed being used in coastal gardens and sheep fleece in the Yorkshire Dales.  All have their pros and cons.

One of the most widely used are bark chippings which are available from most garden centres and DIY multiples, either bagged to take away or in bulk cubic metre bags for home delivery.  They need laying at least 5cm/2ins deep and provide a decorative finish to the soil surface setting off the plantings.

Well-rotted farmyard manure is less easy to come by, but worth seeking out in the small ads in the local papers.  Quality can vary.  If it is well rotted, there will be little smell to it and if it has been properly composted, any weed seeds in the material should have been killed.

Spent mushroom compost is the product left over from mushroom farming.  It usually contains  composted straw and chalk, so is alkaline and shouldn’t be used to mulch around lime-hating plants like rhododendrons and camellias or on soils which are already alkaline. 

Leaf mould is made from composted tree leaves which have been stacked in a heap and left for a couple of years to decompose.   Leaf mould, mushroom compost and manure can also be dug or rotovated into the soil to improve its structure and fertility.

Gravels come in many sizes and colours.  Traditionally they are used on rock gardens, the gravel matching the colour of the rock and setting off the Alpine plants on display.   Gravel gardens would also feature in the top ten of labour saving techniques.  Once planted up and established, they need very little maintenance.  The gravel mulch is best spread over a suitable weed supressing membrane.  Several permeable fabrics are available on the market which will let water into the soil and allow the soil to “breathe”.

The organic mulches are best applied when the soil is moist and has begun to warm up.  Spring is ideal.  Don’t spread the mulch if the soil is frozen or if it is excessively dry in high summer.  The minimum depth should be 5cm/2ins.  Keep the base of woody stems and the crowns of perennials clear to prevent them rotting.  Gravel is inert, so doesn’t break down, get taken into the soil by worms or gradually blow away in the wind.  The other materials are bio-degradable and do, so will need replenishing from time to time.

Jobs for the Month – March

Spring officially arrives in March.  The clocks go forward at the end of the month and we can begin enjoying our gardens for longer in the evenings.

Finish pruning roses, late summer flowering shrubs like buddleias and bush forms of apples and pears by the middle of the month.

There is still time - just - to transplant open ground (non-containerised) herbaceous perennials such as hostas and delphiniums or plants from your garden which you are propagating by lifting and dividing.  Similarly, bare root trees, shrubs and hedging plants can be planted into prepared soil whilst they are still dormant.

Give lawns their first cut of the season.  I hesitate to say “of the year” as many, like us, will have already cut their grass in February’s exceptionally mild weather.  Set the blades at a height of about 3.2cm/1.25ins.

Feed outdoor plants with a general fertiliser such as “growmore” or, if you garden organically, blood, fish and bone.

As soon as snowdrops and winter aconites have finished flowering, lift, divide and re-plant bulbs “in the green” to increase your stock.  Plants propagated this way establish better than dry bulbs planted in autumn.