The Cornus genus covers a very diverse range of about 50 woody perennials but the reason for me selecting them this month is to concentrate on the species and cultivars that provide us with winter stem colour. Few plants can brighten up the winter garden so successfully and withstand whatever weather is sent our way, even this year.
The three main species that provide us with winter stem colour are Cornus alba, Cornus sanguinea and Cornus sericea. I feel these plants are often overlooked by many gardeners as they are very easy to grow and can be commonly found in public gardens.Â Few plants are more noticeable in the shorts days of winter, when they are particularly attractive with a covering of snow below their branches. Additional late winter interest can also be added by planting snowdrops or winter aconites at the base of the plants.
If you have enough space then combining Cornus alba cultivars and Cornus sericea â€˜Flaviramea or Cornus sanguinea Midwinter Fireâ€™ can be an effective contrast of stem colours during the winter months. As well as providing stem colour during the winter months some cultivars also have the advantage of attractive variegated foliage during the growing season.
Â These plants are very hardy and grow in almost any soil. Cornus alba and Cornus sericea in particular are very vigorous and rampant growers and if left un-pruned they can achieve 3m in height and a spread well in excess of this. So for most gardens pruning will be essential to achieve a more manageable garden size of around a metre in height. Although not essential, full sun is recommended for the most effective stem colour.
Pruning also has other advantages as the most intense stem colour occurs on new growth and the plant loses its intensity of colour the older the stem is. To ensure good stem colour it is essential that plants are pruned back to encourage the new growth. This also has the advantage of keeping plants to a more manageable size. Plants should be pruned back to within 2-3â€ of ground level in March just before any new growth starts. If plants produce vigorous growth this should be done every year but if you live in a dry area in the Lothians or have a less vigorous cultivar or very poor soil then you may reduce this to every two or even three years.
Cut stems can be a useful addition to winter floral decorations or stems can be intertwined to make alternative winter wreaths at this time of year.
MyÂ 3 favourite cultivars are:Cornus alba â€˜Kesselringiiâ€™ â€“ Striking stems of almost black/purple, Cornus alba â€˜Spatheiiâ€™ â€“ Attractive bright red stems with the added advantage of gold and green variegated leaves and Cornus alba â€˜Variegataâ€™ â€“ Attractive bright red stems with greyish green leaves with creamy white margins