This Month in the Garden – May 2021

This has been a slow spring with much of April continuing cold and dry.  This has meant we have been able to enjoy the daffodils over an unusually long period but many things have been slow to get going and hard frosts have done some damage.  Seeds that I sowed in my vegetable patch in the middle of March are just beginning to show a tiny bit of green here and there and the onion sets look much as they did when I planted them, and I am writing now in the third week of April.  The ground is exceptionally dry after a long period with no appreciable rain and, unless things change soon, watering will be high on the job list for May.  You will need to pay particular attention to newly planted trees, shrubs and perennials, soft fruit and freshly sown areas.  Established roses benefit from regular watering.  Concentrate on getting the water where it is most needed and, if you have time, use a hose at the base of plants rather than a sprinkler which waters indiscriminately.

If you have been able to start plants off under glass they should be ready for planting out during May but you need to wait until the risk of frost has passed, and that is likely to be at least the middle of the month.  You will also need to harden plants off by putting them out for a few days in the open air during the day and bringing them back to shelter over night; this is where a cold frame comes into its own.  This applies particularly to flowers such as dahlias and geraniums ( pelargonium) and to vegetables like tomatoes ( technically a fruit), cucumber and courgette.  Plants bought from a garden centre or nursery need to be treated in the same way and that applies to anything that was under glass when you bought it, so it can include many annual bedding plants.  Have horticultural fleece available so you can cover plants in the event of an unexpected late frost.

When you plant out dahlias, most will need staking and it is best to put the stake in the ground first so you don’t put the stake through a tuber. Reduce the new shoots to a maximum of three, or even just one, and nip out the tip of each shoot when it has a few leaves so that the plant will branch out.

Early flowering plants will have done their bit by now and some will need dead heading or pruning. If you haven’t done it already this includes dead heading daffodils and fertilising them. A granular feed like Growmore is good for this. The flowering stems of shrubs such as forsythia and flowering currants should be cut back.  Primroses may well have developed new plantlets and these can be separated and planted on. If you are buying plants it is also worth checking to see if a sizeable plant can be divided so that you get more plants for your money. I have just bought a couple of candleabra primulas in pots and each divided into six separate little plants.

An annual application of manure or fertiliser in spring encourages good growth in flower borders and vegetable beds but some plants benefit from much more frequent feeding.  Most plants grown in containers will do much better with a fortnightly application of a liquid feed of a fertiliser like Miracle-Gro and clematis thrive on that sort of frequency with tomato feed. ( so do tomatoes !)  Sea weed fertiliser is also popular nowadays.  If you have acid or neutral soil and you grow camellias or rhododendron or azaleas these should be fed with a liquid fertiliser for acid loving plants, and you should use rainwater rather than tap water.

Owners of green houses should be ready to provide shading as the prospect of hot weather increases. A fairly cheap way of doing this is with a shading product which is diluted with water and painted on the outside of the greenhouse but it has to stay on whether the weather is hot or not. This can be removed by rubbing with newspaper when cooler weather returns.  More flexible types of shading material are available in the form of permanently fitted blinds or netting which can be spread over the glass and put up or taken down as needed.

It is beginning to look as if, at some point during the summer, we shall be able to welcome visitors to our gardens this year, so the effort you put into the garden will be appreciated by others as well as by you.  Alleluia!

Jeremy Arthern

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