Super shrubs
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Shrubs dominate most garden scenes.
Although often overshadowed by trees, they are the bulky plants with growth at
eye level that captures your immediate attention. Yet despite their importance,
any trip through suburbia or even a jaunt through gardens in the country will
reveal that most gardens contain a limited selection of very similar shrubs.
Alright, I suppose that means that we’ve
established which are the good performers and that
they’ve come to dominate. But I feel that landscape gardeners, who stick to
tried and true plants, and garden centres or nurseries that stock or grow
regular sellers only have a lot to answer for.
There's no need to be limited by what
others do. A little searching through the nurseries will reveal a large selection
of less common plants that are often superior to many of the plants that
dominate our gardens. You’ll often find them in the special bins and sales,
which is a pity because they have so much to offer.
That such plants are frequently
overlooked in nurseries or garden centres is due to several reasons. They may
not perform well in containers and so seldom look their best
until planted out; or they may not reach their full potential until quite old;
or they may just lack that instant appeal that makes for a quick seller; or
they may just be out of fashion.
With that thought in mind, I’ve decided
to look this month at a selection of stand-out shrubs that many garden centres
stock but seldom sell. So they are not rare exotica, nor are they ugly wonders
that only a collector could love, or tender beauties that would only survive in
the far north. So out with your Photinia ‘Red Robin’s and Mexican orange blossoms — it’s time for something different.
Agonis juniperina
Popular with florists due to the long
vase life of its flowers, this Australian evergreen is a large shrub or small
tree capable of growing to 5 m high. Pruning after flowering or using the
flowers as cut stems will keep it to 1.8 m.
Its foliage is very fine and needle-like,
as the juniperina epithet indicates. The flowers, which appear from midwinter in mild areas and are the
main feature, are tiny, but massed along the stems in such profusion that they
give the branches a frosted appearance.
Capable of withstanding temperatures down
to at least -6°C, Agonis juniperina
prefers a well-drained, rather poor, gravelly soil and a position in full sun.
‘Florist’s Star’ is a cultivar that is supposedly particularly heavy flowering
though it is not really very different from the species.
Baeckea crenatifolia
In the wild in its native Australia
this is an endangered plant. Here it’s in danger of disappearing from
cultivation because few gardeners seem to be aware of its merits.
It is a wiry-stemmed evergreen with tiny,
bronze-green, oval leaves. In summer the fan-like sprays of branches become
smothered in minute white flowers. As they age the flowers develop a slight
pink tint.
Left untrimmed it will develop into a
rather open bush up to 1.5 m high. However, it is best to cut it back
lightly in late summer to form a rounded shrub. It can even be used as an
informal low hedge. It grows happily in any light, well-drained soil in full
sun.
Beaufortia sparsa
Resembling a small bottlebrush or
melaleuca, the flowers of this 1.2–1.8 m tall evergreen species from Western Australia
are a welcome sight when they start to open in late summer and autumn. Just
when you think the flamboyant blooms are over for the season, vivid orange-red
bottlebrushes appear.
Provided it is lightly trimmed in spring
this is a neat, well-foliaged bush not at all like the untidy, woody
monstrosities that many of the bottlebrushes become. Its Australian common
names — swamp bottlebrush and gravel bottlebrush — suggest two very different
and hard to provide growing conditions. Fortunately it thrives in any moist,
well-drained soil in full sun or part shade. It is, however, only hardy to
about -6°C.
Boronia denticulata
The mauve boronia is a 1–2 m
evergreen shrub from Western
Australia. Unlike the popular
red and brown boronias (B. heterophylla and
B. megastigma), it has starry not
bell-shaped flowers. It is still spring-blooming but is not scented.
Nevertheless it is an attractive and distinctive plant that gives a good
display of pinkish-mauve blooms.
If trimmed after flowering it remains
neat and compact and it is nowhere near as short-lived or fussy as the brown
boronia. Any reasonably sunny, well-drained position out of the worst of the
wind will do. ‘Sunset Serenade’ is a pink-flowered cultivar that is really
quite different from the species.
Carmichaelia odorata
The New Zealand brooms are among the unsung wonders of our native flora. While
superficially like the European brooms when not in flower — wiry or flat
stemmed and largely leafless — they are amazing plants in bloom.
From early December this species, which
can grow to 2.4 m high, produces large panicles of tiny, white to pale
pink flowers with purplish-pink veining. On a still, warm, early summer evening
their scent is overwhelming. The flowers are very popular with the small black
native bees. At the same time tiny leaflets also appear.
Found naturally in the North Island from
Gisborne southwards from sea level to around 750 m altitude, this species
thrives over much of the country under garden conditions. Give it a sunny,
well-drained position and trim only lightly.
Ceratostigma
willmottianum
Near evergreen in mild climates but
almost herbaceous where frozen in winter, this shrub from western China and
Tibet is invaluable for late season colour. It forms a roughly 1 m
diameter clump of wiry twigs that grow from 60 cm–1.2 m high.
The 2.5 cm long leaves are roughly
diamond shaped, bright green when young, develop
coppery tones as they mature and turn to purple before dropping. From early
summer, heads of small phlox-like, gentian-blue flowers open. Borne most
heavily in late summer and early autumn, they are really the only obvious
indication of this shrub’s relationship with Plumbago.
This is a tough shrub that grows well in
most soils in sun or partial shade. If it is not killed back over winter, trim
it back to around half size in early spring to encourage fresh growth and a
compact habit.
Chaenomeles ×
superba ‘Boule de Feu’
That the flowering quinces are still
common garden plants is due more to the longevity of specimens planted long ago
than any current popularity. The pink-flowered C. speciosa cultivars are the types most often seen but I prefer
the more vibrant C × superba hybrids,
especially the vivid reds, of which I consider ‘Boule de Feu’ the best. It
starts to flower around late August to early September as the leaves begin to
develop and produces clusters of intensely red flowers with anthers tipped with
golden pollen. The small quinces that follow the flowers are very aromatic.
It is fairly small for a flowering
quince, around 1.5 m high, and is suitable for low hedging. trim it immediately after flowering. While any soil and
position will do, a cool moist root run and shelter from hot afternoon sun is
best.
Coprosma ‘Beatson’s Gold’
I’ve always liked with this Coprosma cultivar but it seems few
others do. I remember taking hundreds of ‘Beatson’s Gold’ cuttings when I first
started as a nursery propagator. I remember even better having to repot almost
as many plants the following winter after they hadn’t sold.
A hybrid of uncertain origin, ‘Beatson’s
Gold’ is strictly a foliage plant. The name come from
the small ochre to yellow splash in the centre of each of the tiny olive–green
leaves. This is a 1.5 m tall plant that relishes a background role. It is
ideal as a foliage foil to showy perennials or silver-leafed plants. It
withstands severe trimming, almost to the point of topiary, and will grow
almost anywhere.
Crinodendron
hookerianum
Like so many Chilean plants this large
evergreen shrub has deep green leaves and velvety red, lantern-shaped flowers.
It grows to around 5 m high here and needs a cool, moist climate with a
moist, rich soil in partial shade to be at its best. While not tolerant of
drought or hot, dry winds, it is fairly hardy (frosts to -10°C) but is
happier where frosts are irregular.
As a companion for azaleas,
rhododendrons, camellias and other acid soil woodlanders it is unsurpassed. The
very deep green of the leaves tends to make its foliage merge into the
background. However, as soon as the flowers begin to show colour they
immediately grab the attention. Their beautiful colour and texture calls to
mind another Chilean native: the magnificent climber Lapageria rosea.
Cytisus × kewensis
While popular in European gardens, the
reputation of ornamental brooms has suffered among New Zealand gardeners because of the wild Spanish broom (Cytisus scoparius) that is such a weed over much of the country.
This hybrid though, is in no way
invasive. Instead it is a low, spreading plant, around 50 cm high ×
1.5 m wide, that is most at home in large rockeries or spilling over the
top of a bank or retaining wall. It grows in any well-drained soil in a sunny
position. Like most brooms it is very hardy and nothing very exciting when out
of flower. But wait till it blooms. Then the bush totally disappears under a
covering of small cream flowers. Cream may not sound a very vibrant colour but
this is absolutely glowing.
Daphne × burkwoodii
I’ve mentioned previously how it
surprises me that gardeners can lavish so much attention on the often
poor-performing Daphne odora while
ignoring tougher, more easily grown yet equally fragrant types. Granted, this
shrub does not flower in the winter, nor does it have the large glossy leaves
of D. odora, but it is reliably
hardy, strongly scented, not greatly prone to viruses, long-lived and compact.
As might be expected of a cross between
the small, evergreen rock daphne (D.
cneorum) and the tall, deciduous D.
caucasica, it is medium-sized (around 1.5 m high and wide) and
semi-deciduous to evergreen depending on the climate. It flowers from late
winter to late spring and prefers a moist, well-drained, slightly acidic soil
with a position in sun or dappled shade. A variegated foliage form is fairly
common.
Eucryphia cordifolia
This is one of those plants that blurs the distinction between shrubs and trees. Trained to a
single trunk and upright growth it is very tree-like, but if trimmed when young
it remains shrubby. Regardless of how you grow it, this Chilean evergreen is an
impressive plant. Lush, deep green, wavy-edged, oval leaves up to 7.5 cm
long are beautifully complemented by 6 cm diameter, white, camellia-like
blooms that appear from late summer.
Yet this is a plant that usually
languishes unsold in the nurseries. The reason is that it’s not a great
container plant. If you can overlook its gawkiness when young, you’ll be
rewarded when it matures. Like the crinodendron it
does best in a moist, well-drained soil in partial shade. Eucryphia cordifolia however, tolerates alkaline soils.
Fuchsia denticulata
Here’s a fuchsia that’s a little
different in most respects from the fancy garden hybrids. It is a native of Peru and Bolivia
that has distinctly bluish (glaucous) foliage and unusual tubular flowers.
While the foliage is interesting, the flowers are undoubtedly the main
attraction. They green-tipped deep pink tubes up to 7 cm
long. When open they reveal a corolla of bright orange petals.
Purplish-red, 2.5 cm diameter berries follow the fruit.
This species resembles the tropical F. triphylla hybrids but is considerably
hardier. Nevertheless it will not tolerate regular hard frosts unless very well
established, in which case it will often reshoot from the rootstock. Like most
fuchsias it prefers a humus-rich, cool, moist, well-drained soil in dappled shade.
In the wild it can grow over 5 m high but seldom exceeds 2 m in New Zealand gardens.
Grevillea victoriae var tenuinervis
Like almost all grevilleas an Australian
native, the rusty-red-flowered Grevillea
victoriae has long been recommended as a plant that tolerates extremely
tough conditions. But while there’s no denying that it’s tough, I’ve always
thought it to be a rather nondescript shrub. The introduction of variety tenuinervis has changed my opinion
though.
This variety is like an improved, more
vigorous version of the species. Its leathery, deep grey-green leaves are
larger, up to 12 cm long, and its flowers are bigger, brighter and more
numerous. If you are familiar with the species and have been inclined to ignore
it, don’t automatically write off var. tenuinervis.
It is very hardy for a grevillea (frosts
to -8°C) and tolerates most soil types provided they are well-drained and
not alkaline. A position if full sun is best.
Hydrangea aspera
Hydrangeas generally fall into the love
’em or loathe ’em category, but here’s a hydrangea that receives almost
complete approval. And that goes for me too, even though I verge on being an hydrangea hater.
The overall effect is rather like a
lace-cap hydrangea. The 15–20 cm diameter flower heads are composed of a central
mass of tiny, purplish-pink fertile flowers with an edging of white to mauve
sterile bracts. Carried above the pointed oval, 25–30 cm long leaves, the
flowers, foliage and layered branches create a very graceful effect.
Found naturally over much of the
temperate and high altitude zones of Asia, Hydrangea aspera will
tolerate full sun but does better in partial shade. A moist, humus-rich soil
will produce the best foliage. Unlike the hortensia hybrids, the flowers do not
show much colour variation regardless of the soil pH. It is often sold under
the old name Hydrangea villosa.
Kolkwitzia amabilis
That this tough, heavy-flowering and very
beautiful 2.5 m high deciduous Chinese shrub is now uncommon is simply the
result of gardens becoming smaller and deciduous shrubs in general falling from
favour. While some deciduous old timers like the Philadelphus have made a comeback, the beauty bush has not.
Upright, bare winter stems come into leaf
in early spring. The leaves are soon followed by clustered pairs of pale pink
flowers up to 2.5 cm long. The effect is very like the closely related Weigela florida except the stems are more like a series of canes than a shrub. This
enables it to be trimmed by shearing rather than careful pruning. It tolerates
most soils that are neither poorly drained nor very dry and prefers full sun.
For cool-climate, country gardeners there can be few better shrubs to use for
screening or low shelter.
Osmanthus delavayi
Once quite popular, this evergreen shrub
from western China is now seldom planted. And that’s surprising because it is not
difficult to grow and few plants can match the scent produced by its
1.5 cm, white, tubular flowers.
Admittedly for most of the year it tends
to be a rather uninspiring deep green shrub that doesn’t exactly leap out and
grab your attention, but for few weeks from early spring its clusters of
flowers can scent a garden. Small black berries follow the flowers.
Osmanthus is not a fussy shrub. It thrives in any well-drained soil in sun to near full shade. It usually flowers more heavily in a fairly open position.
Pimelia longifolia
The tarata used to occur over most of the country but is now uncommon. However, it adapts well to cultivation if given a fairly rich, well-drained soil with sun or part shade.
One of our most attractive medium-sized native shrubs, it has narrow, light to mid green leaves up to 7.5 cm long and from mid spring the heads of small, fragrant, white flowers open. The overall effect is rather like the widely grown Australian shrub Eriostemon myoporoides.
An evergreen that varies in height from 60 cm to 1.8 m high, this shrub can be trimmed to shape after flowering. It is hardy to about -8°C. This really is a plant that deserves to be more widely grown.
Viburnum trilobum
Viburnums are widely grown and highly regarded for their flowers, foliage and scent. One feature often overlooked however, is their fruit. This deciduous species from North America is sometimes called the cranberry bush and when seen in autumn, laden with bright red fruit, it’s not hard to see why.
That fruit begins life in the spring as a small white flower borne on a flat-topped head above three-lobed maple-like leaves. By February the berries are nearing full colour. They are a brilliant sealing wax red that really glows.
In the United States there are many named cultivars. In New Zealand however, we are largely restricted to the species, which can grow to 3 m high. It prefers a rich, moist, well-drained soil in sun or partial shade.
Weinmannia racemosa
Kamahi honey is in every supermarket, but when did you last see a kamahi in a garden? While this large evergreen shrub is very hardy and one of our showiest native plants, it’s not widely cultivated.
In the wild it can develop into a tree up to 20 m tall, but in gardens it remains a 1.5–3 m high shrub for many years, especially if trimmed occasionally. The bottlebrush-like spikes of cream flowers appear from late spring and carry on through mid summer with sporadic bursts possible at almost any time.
The leathery foliage is also very attractive. Reddish brown when young and often used in floral decorations, it matures to a deep, slightly lustrous, olive green. A purple-leafed cultivar is occasionally seen.
Kamahi is easily grown in full sun to moderate shade in any soil that is well-drained and never gets bone dry.
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Any one of these shrubs alone will probably not make much difference to your garden, but get a few of them together and your patch will begin to take on some individuality.
Copyright Geoff Bryant
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