In the Garden: January 7, 2011

• Now is the time to get straight on to dividing and replanting autumn bulbs because they will be starting to come into growth very soon. Belladonna lilies and nerines both get planted with their necks above ground level. Cyclamen hederafolium (I spotted the first flower this week), sit just nestled into the soil, like round discs. Their roots and their flowers both come from the top so it does help to get them the right way up. Ornamental oxalis and colchicums (autumn crocus) are other common autumn bulbs to divide now.

• Summer is the best cherry pruning time to avoid the dreaded silver blight getting in to the cut surfaces. If you have a flowering cherry with patches which did not flower last spring and the leaves are clustered much more densely, you have witches broom which needs to be cut out before it takes over the entire tree. Unfortunately the very popular Prunus Awanui is susceptible to witches broom, as are many other ornamental cherries of the Japanese type.

• You can cut most hybrid clematis off close to the ground if they have finished flowering or are looking mildewed (powdery white leaves). Feed them, keep them watered and they will grow again and flower in six weeks. This works for most of the large flowered types.

Arum lilies may be prized as cut flowers overseas but one look at the root system shows why they are a noxious weed on the banned list here

Arum lilies may be prized as cut flowers overseas but one look at the root system shows why they are a noxious weed on the banned list here

• If your New Year’s resolution was to start a vegetable garden, start preparing the ground now for planting winter vegetables soon. It needs to be in full sun. If you make the effort to get the soil right, it will pay dividends. If you are starting with lawn or grass, skim off the turf before you start digging and stack it to one side to rot down. Then start digging, and digging again to get the soil light and friable. Add in compost or manure and then leave it all to settle, push-hoeing off any germinating weed seeds as they appear.

• Garlic can be harvested now, but leave onions until the tops turn brown and bend down. To store garlic for the rest of the year, it will need drying – plaiting and hanging is the traditional method but you can also lay it out in a well ventilated area. Super fresh garlic is delicious to use in cooking.

• Arum lilies are a menace and on the banned list. I dug out a few remnant plants of the green and white flowered form called Green Goddess. You can see in the photograph how the roots are a rhizome with a multitude of little round babies ready to detach from the main body and to grow. These need to removed from the site too or they will continue to cause problems. We put them out in the rubbish, rather than trusting to the composting process and I will keep checking the area on the look out for babies germinating.