April 2023

By the time you read this, day-light will be longer than night-dark. The dynamic awakening of spring will be well underway. Leaf buds on most deciduous trees will have burst open, revealing the billions of little green oxygen producing solar panels that we all depend on and call leaves.

Deciduous (Latin deciduus) plants (decide to) cause their leaves to “fall off ” ready for winter, and re-leaf each spring. This plant behaviour is confined to a relatively narrow band of global temperate zones. The alternative is to be evergreen, like our native Scots pine, juniper and yew. All other conifers are alien. Holly is the only truly evergreen British native broad-leaved tree. Box is native, broad-leaved and evergreen, but is generally considered to be a shrub. All other broad-leaved evergreen trees, such as holm oak, or bay (laurel) are alien. Bay is a true laurel, and supplied the leaves that made up Julius Caesar’s laurel crown. The garden hedge-plant often referred to as laurel is a species of cherry in the Prunus genus. Its full name is cherry laurel. This species, like Rhododendron, has become an ‘Alien Invader’ and colonised many ancient woodlands with problematic consequences. All plants in Britain are either alien or native and invasive or non-invasive. An example of a native invasive plant is bracken. A non-invasive alien example is Dahlia, which is native to north and central America. A native non-invasive example is pyramidal orchid. Two examples of invasive non-native species are noted above. These inhibit and outcompete native species.

Ivy is clearly not a tree, but a native climbing vine. Being evergreen gives ivy a function similar to holly. Owls like to roost during daylight in ivy-clad trees. Honeybees and other insects feed on nectar from ivy during autumn, because ivy is one of the last plants to flower. The berries of ivy, yew and holly feed countless birds especially woodpigeons during the winter. The seeds of these plants pass through the bird’s body and are dispersed throughout the woodland to germinate and produce new trees, or climb up old ones. Ivy-clad trees provide a roosting and hibernating habitat for many species of animals, especially invertebrates. Ivy rarely kills trees, but just uses them for support, may limit their branching ability, make them wind-opaque and may hasten their demise.