Winter washes Still a worthwhile operation using Certis Spraying Oil on green conifers as well as trees.
For control of over-wintering mites on Picea, this is a good practice. Make sure that there is no rain or frost for 24 hours after application and no young soft growth.
Botrytis Keep up sprays of Rovral WG, Scotts Octave and Serenade ASO (SOLA 2009-0246) this month. Ventilate tunnels to keep air fresh around foliage.
Grasses These can show signs of powdery mildew from now into February. Spray with Systhane 20EW or Nimrod.
Hydrangea Consider moving hydrangeas under protection. The recent very cold weather should have stimulating bud initiation.
Choisya These plants often suffer from snail damage at this time of year, which can spoil an otherwise quality plant when it comes to marketing. Apply Ferramol pellets, which are safer to apply if animals or birds are present and breaks down to plant nutrients. It is rainand irrigation-fast, leaves no residues and not only kills slugs and snails but is an attractant too. Other pellets, such as Decoy Wetex, are available that also resist decomposition for up to six weeks. Order your Choisya liners early — I have found that potting them in March gives a much higher survival rate than those potted from May onwards.
White blister Check Aubretia and Arabis and spray with Amistar (SOLA 200-0443) or Signum (SOLA 2009-1842) if you see the white fluffy growth on the underside of the leaves. If you grow cabbage outdoors or even young cabbage plants, these too can be affected by this disease.
Field crops The last week of January is often dry and is an ideal time to make that first nitrogen top dressing to tree crops. In line with current legislation, consider slow-release nitrogen products such as Entec that regulate the nitrogen flow and reduce run-off and water pollution.
Cold stores Watch the temperature and humidity levels in cold stores during changeable days. Spray stored material with Bravo 500 as protection against fungal growth on stems and old foliage. Milder autumns can result in more old foliage left on stems, which results in fungi.
Root cuttings Time to take root cuttings of herbaceous perennials such as poppies and Phlox. It is surprising just how small pieces of root will grow in some cases. Even the leftover tails put into a tray of compost will provide new plant material in the spring.
John Adlam is managing director of Dove Associates