Wider choices for narrow spaces
Fastigiate plants solve the cramped confine conundrum
WITH the size of residential blocks in our larger towns and cities gradually becoming smaller and smaller (but not the cost!), it’s becoming quite a challenge for residents of these cramped plots to select plants that won’t outgrow their somewhat confined and usually narrow spaces.
One of the greatest challenges for these gardeners is selecting shrubs and trees that will conform to spaces not exceeding anything wider than, say, 1 to 3m, but still growing tall enough to create a sense of scale against a single or sometimes double storey residence.
Luckily for those who find themselves faced with this conundrum, plant breeding and careful selection over the years has produced a growing range of narrow, upright plants that will fit nicely into smaller spaces created by ever-shrinking block sizes, but that are also ideal for any narrow space in an existing garden where “normally-dimensioned” plants simply won’t fit, such as between a driveway and a fence.
In describing the form of these plants, horticulturists use the word “fastigiate”, meaning branches that point upwards in almost parallel lines, or a columnar shape. Common descriptive names, seen in catalogues or on plant tags, are usually ‘Fastigiata’, or “fastigiate form”.
Here’s a few fastigiate forms of popular and widely grown shrubs and trees that will grow in and around our region.
When it comes to selecting narrow, upright shrubs and trees for that tight squeeze in your yard, you can’t go past the large range of conifers that fit the bill.
No doubt the most recognisable plants of this group are the pencil pines (Cupressus sempervirens var. stricta), tall (10-15m), stately pines commonly used in large, formal gardens in their native Italy.
Their tight, columnar form and eventual height demands a degree of caution when using them in smaller gardens, but there’s very few plants that will rival their impact if used singularly, in rows, or clumps.
Quite tolerant of all but the harshest of climates, they prefer to grow in a moist, loamy to clay-loam soil, and are more at home in cooler, elevated areas. Look too, for the Golden pencil pine, ‘Swane’s Golden’, and a shorter NZ cultivar, ‘Gracilis’.
Other conifers conforming to this narrow, upright description are Juniperus scopulorum ‘Skyrocket’, only around 50cm wide at its base, and growing to maybe 7-8m tall, Juniperus communis ‘Compressa’ (1m H x 30cm W), J. communis ‘Gold Cone’ (2m H x 70cm W) and J. communis ‘Hibernica’ (3-4m H x 80cm W).
Staying with the skinny pine trees, you can try Thuja (pronounced “thoo-ya”) occidentalis ‘Fastigiata’ (6m H x 1.5m W), and one of my favourite pines, Taxus baccata “Fastigiata”, the Irish yew, growing to 4m by about 60cm in my garden in 16 years.
Don’t forget that there’s been some huge steps in breeding Australian native plants lately, and this has included the lilly pillys and bottlebrushes.
A tall, upright lilly pilly worthy of that narrow space in your garden is Syzygium australe ‘Pinnacle’, possibly growing to 10m high but only about 1.5m wide.
However, this plant can handle heavy pruning so can easily be held at heights from 2m upwards. Another recent release is Callistemon viminalis ‘Slim’, growing to around 3m by 1.3m.
It’s tolerant of a wide range of soils, and is claimed to be hardy in dry conditions and tested through frosts down to -6° C. The great advantage of this plant is that it will still flower well even if it’s pruned to a hedge shape.
Some of the hardiest of all the narrow and columnar plants are a number of small to medium exotic deciduous trees such as the pears (Pyrus), plums (Prunus) and, surprisingly, even a maidenhair tree (Ginkgo).
Ideal for narrow car park beds, footpaths and slim side gardens, Pyrus calleryana ‘Capital’ will grow at a moderate rate to about 10m high by 3m wide. Pyrus are known for their tolerance of a range of soil types and pretty tough conditions such as heavy air pollution, making them an ideal street tree along busy thoroughfares.
They’re quite a sight in spring as well, sporting brilliant white flowers before the leaves appear.
One of the most dramatic small trees for a narrow space is the fastigiate form of the dark-leaved cherry plum, Prunus cerasifera ‘Oakville Crimson Spire’.
The almost-purple foliage of this 6m x 2.5m tree makes for a wonderful contrasting statement in a garden, but is most outstanding when in an avenue planting.
Not quite as tough as the Pyrus, this tree will need full sun and a moist, good quality soil to produce its deepest foliage colours after a display of pink flowers in spring.
It’s not surprising that there is a narrow, upright variety of the beautiful maidenhair tree, Ginkgo biloba ‘Princeton Sentry’.
Whilst not a tree for a tiny garden, this variety is a much narrower form of its wide-crowned parent, only growing to about 4m wide whilst hitting around 12m in height. This tough, deciduous and unique tree is one of only a few that turns a brilliant golden autumnal hue.
Whilst most of these fastigiate shrubs and trees are self-shaping, watch out for and remove errant stems and shoots growing at odd angles to the normal foliage, as they’ll quickly spoil the desired form of the plant. And don’t forget to nip any suckers off grafted plants as well.