This Month in The Garden, March 2012 with Derek Cox

It always surprises me to see how resilient many winter flowering plants are to frost. During hard frost, the snowdrops will fold their flower stems down to soil level and as soon as the temperature rises, the stems will lift the flowers back up into their original position. I have three different Hamamellis, pictured left, witch hazels, in my garden, which give an outstanding display of yellow flowers from January until March; the petals of these will roll inwards during hard frosts and then unroll as soon as the temperature warms up. Snow will give me a very different problem as its weight, especially as it starts to melt, will crush the stems of the taller growing snowdrops and unless it is knocked off, will break branches, or open up conifers. Odd though it may seem both snow and frost do not seem to affect Cyclamen coum whose flowers seem to stand upright and push through light snowfall. The foliage of my Crocus will stand up like soldiers through even three inches, 7.5cm of snow, the snow does delay the flowering, but they still put on a good show. Most of my Helleborus hybrids are in full flower by early February, but this year all of those in my back garden came into flower three weeks later than normal.

However, Helleborus ‘Walbertons Rosemary, pictured right, which grows in my front garden opened its rich pink, outward facing flowers during January and is still in full flower. What a shame it does not set seed and is slow to form a decent clump. In the February addition of the RHS journal ‘The Garden’ there appeared a photograph of Helleborus ‘Anna’s Red’ and this appears not only to have outward facing flowers, but they are also a rich red. I rang RD plants in Devon and they informed me it will not be available until next year. Incidentally, most Helleborus hybrids produce an immense amount of seed, which seeds itself all over my garden, the seed requires cold germination and in the open ground, hundreds of seedlings appear during the first week of January. Pinus mugo is the dwarf mountain pine, which I have seen high in the Swiss mountains as low growing knarled conifers. I grow a form of this named ‘Zundert’ and this is an oddity in that during November, as the weather turns cold the dark green foliage starts to turn yellow. This and other dwarf forms of the mountain pine are often found in garden centres as small grafted plants, but when grown in good garden soil they will often grow much taller than they would on a mountainside. My twenty-year-old plant of Zundert is now four feet, 1.2m tall and I prune it every June to keep it compact. When pruning pines do watch out for the resinous sap, if this gets onto your clothing you may find it very difficult to get off.

During early February, I went along with BBC Radio Leicester to record a ‘Down to Earth’ programme at Tilton on the Hill. The weather was awful, but this did not deter Helen Osborn’s partner Bob from driving along snow-covered roads there, and into a blizzard on the way home. One of the questioners brought along a branch of Hibiscus rosa-sinensis, this had a superb large red flower attached and the question was how do I propagate it? For those of you who do not know this plant, it is the flower often depicted in the hair of Hawaiian girl dancers. The plant in question was growing in a pot in a warm bay window and it had become straggly. I grow the same shrub in my conservatory and as the plant; flowers on its new wood prune it hard back during March. Then, during May, when the new growth is about three inches, 7.5 cm long, I take cuttings that are just becoming firm, strip off the bottom half of the leaves and then put the cuttings in pots containing a mixture of half peat and half perlite. Keep the cuttings moist, but not wet and stand in a warm, but not sunny spot. Cuttings will usually root in four to six weeks.