Growing season: a month in the country with Bunny Guinness
My month in the garden How polytunnels make life easier, lessons learned from a master rosarian and the simple pleasures of a bound gravel surface
SOIL TESTING
I am often asked about good home soiltesting kits. When I was studying horticulture at Reading many years ago, I seem to remember we tried out several kits and compared them with accurate lab tests. The conclusion was that the kits were really not accurate enough to be useful. Talking to Tim O’Hare (top soil scientist – toha.co.uk), he says this is still true today.
In laboratory tests, demineralised water is used rather than tap (which can affect accuracy) and the lab temperature is a consistent 20C (not usually the case at home). Both these factors, plus others, influence the results. Better to send samples away to a lab such as NRM (cawoodscientific.uk.com) and get an accurate test for £12.13 plus VAT. This will test for P, K and Mg plus pH (phosphorous, potassium and magnesium plus acidity/alkalinity). When testing a lawn or borders, O’Hare recommends taking soil samples from six to 10 places, mixing the soil in a bucket and then sending off the “composite sample” for testing. Most gardeners would only tend to do a soil test if there was a problem, but some of us like to know anyway – and I often do this for clients.
To take samples, remove soil from just the top 15cm, excluding any grass or mulches. You need about 400g for each sample. Royal Horticultural Society members can send samples to the RHS, which it sends on to NRM. The advantage is that the RHS will explain what the results mean, analyse the texture and what you need to add for borders, veg and lawns. This service does cost a little more, though (£30 for members, £35 for non-members).
O’Hare was checking a lawn recently. These apparently can often be low in potassium, which leads to chlorosis and can make the grass more susceptible to red thread and other diseases. A good way to correct low potassium in a lawn is to add a fine green compost (e.g. local authority green waste, which is high in organic nitrogen and potassium). This can be applied as a top dressing. It will increase the organic matter and the quantity of soil microbes, too.
It is now thought not good or necessary to add chemical forms of nitrogen fertiliser to soil as there is wastage (into water courses, potentially) and you get too much quick top growth at the expense of root growth.
For wild flower meadows, the phosphate level of the soil is often too high, which allows grass to dominate. So, prior to establishing meadows, I often get soil tested. The ideal soil for meadows would have less than 10mg/litre of extractable phosphate, or certainly less than 20mg/litre – which is what the soil test can tell you.
If you just sow into subsoil, it can be so low in nutrients it takes three to five years for the wild flowers to establish well. To counterbalance this, you could add some green compost to kick-start the process.
A LIFE IN ROSES
I was chatting to Michael Marriott (the renowned rosarian) recently about rose replant disease and discovered he had left David Austin Roses, where he worked for more than 35 years.
He is now spending his time lecturing, running workshops, designing gardens, writing and doing garden tours, as well as dispensing invaluable advice on roses when required.
Marriott read agricultural botany at Reading University and, after working (mainly abroad) for five years, went for an interview with David Austin Roses in 1985. He met the late David Austin and this triggered a passion for old roses and David’s English Roses.
Marriott joined a small team (about eight staff) and became the nursery manager. This was around the time that Rosa ‘Graham Thomas’ was launched, quite a breakthrough as it is an unusual, rich, pure yellow and this sumptuous rose caused a real stir.
His work changed over the years. He concentrated on lecturing, meeting important clients, travelling the world to set up rose trials, advising on roses. He also designed many notable rose gardens, including the mixed borders in Queen Mary’s rose garden in Regent’s Park and the rose garden in Kew Gardens.
He often uses the dependable, repeatflowering English Roses. His favourites include ‘Princess Alexandra of Kent’, ‘Princess Anne’, ‘Desdemona’, ‘Vanessa Bell’, ‘The Generous Gardener’, ‘Kew Gardens’ and ‘Eustacia Vye’. Although people often demand repeat-flowering shrubs, he likes to include some onceflowering old roses, too, maybe some gallicas or damasks, such as ‘Queen of Denmark’, ‘Celsiana’ and ‘William Lobb’.
He also tends to weave perennials, annuals and biennials into the melange, too. Especially Phacelia tanacetifolia, the fiddleneck. This pretty blue annual can be sown at almost any time of year, bees love it, it is a great cut flower and will self-seed. For a succession of flowers, sow it every eight weeks or so (michaelmarriottrosarian.org).
GRAFTING APPLES
I have not done any whip and tongue grafting since my student days nearly 50 years ago. But I had a fabulous refresher by way of a Zoom course from The Newt hotel in Somerset last month, which is famous for its apples. It was the perfect way to learn.
In advance, a mass of bud wood (scion), rootstocks, wax, tape and a knife were sent, together with a grafted plant of ‘Yarlington Mill’ a cider apple variety.
Then, over the course of an hour at my kitchen table, Andy “Apples” Lewis, who looks after fruit trees at The Newt, coached us. By the end of the session, we all had three trees we had grafted.
The Newt is offering a Zoom course on the Three Sisters planting method on April 27 (£30) and all the kit will be sent out in advance to attendees (to book, visit thenewtinsomerset.com).