Many shrubs that grow tall also grow bushy – a fact sometimes overlooked in the quest for screening or privacy. Defining what a tall shrub is can be fraught by problems, for no two gardens (or gardeners) are alike. Some would consider 6 feet (1.8m) to be tall; for others, that would be a medium sized shrub.
This list is by actual physical height that can be reasonably expected in around ten years of growth. Some shrubs will reach full mature size in just a few years, whilst others will eventually get there in a more leisurely timeframe. All of the shrubs mentioned, will carry on growing – sometimes well in excess of the 1.8m guide.
To give an idea on size, the highest fence panels are normally 1.8m tall. So this list of shrubs will extend over the top of the fence within 10 years maximum.
There are a wide range of conifers – NOT Leylandii please – that will qualify as tall evergreens – a different article.
Many evergreen shrubs also flower, but those are covered elsewhere. In this list the predominant feature is the fact that the shrubs are evergreen – maybe with incidental flower interest. Many will be borderline cases in that respect. For instance, Viburnum tinus is sought for being a winter flowering shrub, but is also a superb, if uninteresting evergreen.
Prunus laurocerasus - the Cherry Laurels – have to be at the top of the list because of their varied evergreen foliage. They will give dense cover and a short spell of white ‘candle’ flowers for those that are not clipped. They will easily attain a height of 1.8m and beyond, and a spread of approx 60% of the ultimate height. Can be pruned hard, or clipped for a more formal shape.
The Cotoneasters are varied with deciduous, low and spreading types – important to get the right variety. Some – whilst tall growing – will develop into small trees with bare lower branches. This is useful if you want to plant shade loving plants beneath. The best of the batch that will remain clothed down to ground level are Cotoneaster ‘Cornubia’ – which will have a spread almost comparable to its height; Cotoneaster lacteus is similarly arching, so clothed to the ground. Both have the added attraction of reasonable white flower display in summer followed by masses of red berries late into winter.
Viburnum tinus would seem the obvious choice for evergreens, but we will leave that for the list of flowering evergreens. Instead I will opt for that rarely-planted Viburnum rhytidophyllum – the large leaved Viburnum. It is sometimes referred to as semi-evergreen. It is not, it is fully evergreen. 1.8m is absolutely no problem in about five years. The wrinkled spear-like leaves – leathery and glossy – are sometimes 8 – 10 in long. Yes, it flowers as well, but they can be largely ignored in favour of the spectacular foliage. Remember the name, because visitors to your garden will want to know what it is.
Fargesia murieliae is the one I would opt for. It is clump forming, fully evergreen and hardy. It does not spread as do some of the other bamboos. Most of the foliage tends to be at the top of the plant, but it can be fully clothed to the ground if growing well. 1.8 is easy in 5 years, with a not to problematic spread of a metre or so when mature.
The firethorn has to be included as an evergreen – though firstly thought of as a berry shrub – for it brings a new dimension. That of thorns! It has small, dark green glossy leaves – which sometimes get scorched by drying winds – but soon recovering. It is best against a fence with support, rather than as a free standing shrub. The thorns will repel any unwanted visitors, and often cause problems for unwary gardeners!
Holly – I am skipping for it is really a single stemmed small tree.
The Red Robin Shrub is a super addition to any evergreen list, and the brilliant red young foliage gives rise to its descriptive common name. A little slow to get to 1.8, but will certainly do it within our 10 year time frame. Slightly open habit of growth unless clipped, but still a good screening shrub which will top the 1.8m, bringing it on to this page,
Laurus nobilis. Forget the clipped specimens in pyramidal or globular shapes. Here we talk of the Bay as a free standing evergreen shrub. Hardly needs description as an ornamental shrub, but little realized that it can soon get to 1.8m and well beyond. A redeeming factor being that it can be clipped or hacked even to keep it to size. The bay is a dense evergreen with dark foliage, that sure to block out any undesirable view.
The Oleasters are normally grown for their variegated foliage, but one that deserves to be included here, and would have a space in any garden I built – is Elaeagnus ebbingei. The upper surface of the leather leaves is grey green – almost metallic in appearance – whilst the undersides exhibit downy silver to cream colour which makes them doubly attractive in a light breeze. Other than the fact is is a good evergreen, with an upright then spreading habit, it has small insignificant tubular flowers – not often but noticeable by their fragrance. A scent that will hold its own with most other scented flowers. This happens in November – hence the fact the flowers are rarely sighted!