Holly and the Ivy Evergreen
Two of our very few native evergreens, holly and ivy, are as seasonally synonymous as Christmas and pudding. For our forebears, these were plants that mysteriously denied the seeming extinction of nature during winter's icy grip and, to this day, we retain the ancient custom of decking the house with these evergreen plants to subdue sprites and goblins over the festive season.
Our only evergreen liana, Ivy's capacity to climb depends on its ability to produce adventitious roots along its new shoots. These function primarily as, very tenacious, anchors but have little or no capacity to penetrate surfaces and absorb moisture and nutrients. Tales of ivy parasitizing trees or destroying buildings by renting them asunder with their "roots" are based on misunderstanding. Anyone who has severed the top of an ancient ivy from its terrestrial roots and watched it slowly brown and die is witness to its dependence on having its feet firmly in the ground! Any destructiveness is based on, firstly, the structural condition of its host and, secondly, the sheer mass of foliage generated by a mature plant. If a tree is structurally unsound the additional stress generated by the weight of the ivy can be the proverbial straw that breaks its back and even healthy trees can be toppled by the sail-like drag of a full head of the stuff. Equally, old walls can subside under its pressure and flaky mortar be dislodged by its movement or the vigour of its removal by a zealous gardener.
Like humans ivy manifests its transition from fresh faced youth to hoary old age by altering its appearance and pattern of behaviour. In its prolonged juvenile stage it is a vigorous creeper and climber with multi-lobed leaves arranged in one plane which forms a dense mosaic. In maturity, it stops climbing and produces bushy, upright growth clad in unlobed leaves arranged spirally around stems that flower and fruit in late autumn. It's this growth which tends to cause the problems so management is essential. Make it a New Year Resolution and once a year, generally in early spring as they come into growth, prune ivies back to their allotted spaces. We mercilessly shear them back to their bare stems to keep them in juvenile mode and removes all of last year's tired looking foliage and guarantees a mat of fresh, glossy growth for the summer.
Ivy is just as happy to creep horizontally as vertically and will grow in deep, dry shade. Under the crowns of heavily shading evergreens like yew, its glossy green foliage reflects the heavily dappled light and produces a unifying and strangely soothing effect unachievable with virtually anything else.
A Jolly Holly Christmas
Holly is a large genus of over 400 species distributed throughout the world. Our native species, Ilex aquifolium, has generated enough cultivars and varieties to keep most "Ilexophiles" happy. In the wild it can be found as a shade tolerant, woodland under-storey tree made spindly by lack of light. Equally, it may grow as a single, densely foliaged hedgerow or field specimen. In the garden it makes a marvellous and impenetrable hedge but you do need patience. Holly is one of those annoying plants that seems to self-sow everywhere but which sits and sulks for years when you plant it. Plant in May or September, when the roots are active, and even then it's a good idea to reduce the crown by up to one half. Tolerant of most conditions it will thrive best on a moist, well-drained soil and in full sun, particularly important for the numerous variegated varieties or for any attempts at topiary. Like yew or box it will regenerate if cut hard back to the main framework branches or trunk, and so rejuvenation of straggly old specimens is feasible.
As most holly is either male or female you will disappointed unless your tree has a companion to mate with! Either rely on friendly neighbours or specify a "couple" (not necessarily of the same variety) when ordering. Although anything other than crimson berries feels wrong at this season, I.aquifolium Bacciflava, Pyrimidalis Fructu Luteo and Amber all have distinctive yellow berries and smooth leaves, whilst I. crenata has black. Foliage offers even more variation ranging from the male and fiercely prickly Hedgehog holly, I.aquifolium Ferox, through to the silkily smooth and shiny I. x altaclarensis Camellifolia, the bright golden variegation of I. x altaclarensis "Lawsoniana" and the daintiness of I. crenata.
But whether it is berry or leaf the holly and the ivy aren't just for Christmas, they're for life.