New Zealand’s native brooms: Overlooked treasures?

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6 New Zealand Garden Journal, 2016, Vol. 19(1)
New Zealand’s native brooms:
Overlooked treasures?
Murray Dawson1
New Zealanders typically think of
broom plants growing in the wild as
rampant weeds, because they are
so familiar with the widespread and
exotic common (or Scotch) broom,
Cytisus scoparius (Fig. 1A–C), and
the Montpellier broom, Genista
monspessulana, which are invasive
in disturbed and sunny areas such
as riversides, forest tracks and open
hillsides. These infested areas are
blanketed in seas of bright yellow
owers, followed by pods that
explosively disperse seed several
metres in all directions. Branches of
European species were traditionally
used for sweeping which explains the
common name “broom”.
In comparison, New Zealand’s native
brooms contain some remarkable
rarities that should not be tarred
with the same brush as their weedy
European cousins. Make no mistake –
our native brooms are treasures with a
wide range of interesting growth forms
ranging from prostrate shrubs (only
2 cm tall) to spectacular trees (up to
10 m). They are predominantly leaess
and are able to photosynthesise
through attened or cord-like stems
called cladodes. Most native species
have purple owers, although colour
varies from pale lavender through to
intense pink – creamy white or yellow
owers are much less common.
Several native brooms make excellent
garden subjects and deserve to be
more widely grown. Most native brooms
are very hardy when planted in full sun
and free-draining soils and few tolerate
heavy shade and high humidity.
Along with native species including
kakabeak (Clianthus spp.) and kōwhai
(Sophora spp.), brooms belong to the
legume family Fabaceae, which is why
they have pea-like owers. Legumes x
atmospheric nitrogen through special
root nodules and therefore cope well
in poorly developed soils. Their seeds
usually have very hard seed-coats that
need to be scaried – in other words,
they must be chipped or otherwise
treated – to enable them to germinate.
New Zealand’s native brooms all
belong to the genus Carmichaelia.
23 out of 24 currently recognised
species of Carmichaelia are endemic to
New Zealand – that is to say, they are
unique to this country (Table 1)2. Native
brooms are found from the Far North to
Stewart Island in a variety of habitats,
from coastal to alpine. The proliferation
of morphologically diverse but closely
related species in Carmichaelia is a
good example of adaptive radiation
in the New Zealand ora – the rapid
diversication of species to occupy
ecological niches – as found elsewhere,
for example, in our native Coprosma
and Veronica (hebes).
Although Carmichaelia is distributed
throughout New Zealand, many are
threatened, including a high proportion
of species restricted to drier eastern
areas of the South Island. Most
New Zealand native brooms prefer
disturbed and open habitats which
mean they are vulnerable to erosion
and being out-competed by weeds in
the lowlands. Furthermore, our native
brooms are highly palatable to a wide
array of browsing animals, ranging
in size from rabbits and hares up to
possums, sheep, goats and deer – all
of the introduced herbivores seem to
munch them!
Because of their high conservation
values, native brooms should not be
removed from the wild. Unfortunately,
some plants (such as the Canterbury
pink broom, Carmichaelia torulosa)
have accidentally been killed in the wild
by herbicide spraying through being
confused for the weedy exotic brooms.
In this article, I will provide an overview
of this remarkably diverse native
plant group, covering all low growing
species, and a selection of shrub and
tree species suitable for cultivation.
If you are interested in growing
New Zealand’s native brooms, there is
a good range available from specialist
native plant nurseries.
A
B
C
Fig. 1 Cytisus scoparius growing as a weed
on Banks Peninsula, Canterbury. A, plant still
in ower mid-winter. B, close-up of ower.
C, close-up of old twisted pods that have
ejected their seeds. Photos: Murray Dawson.
1 Landcare Research, PO Box 69040, Lincoln 7640, New Zealand; dawsonm@landcareresearch.co.nz
2 The remaining species, Carmichaelia exsul, is endemic to Lord Howe Island. “Exsul” is an apt species name as it is Latin for “exile”, and its
ancestor probably dispersed to Lord Howe all the way from New Zealand.

New Zealand Garden Journal, 2016, Vol. 19(1) 7
Table 1 New Zealand native species of Carmichaelia.
Botanical name Common name(s) Growth habit and distinguishing features
*C. appressa G.Simpson Appressed broom,
prostrate broom
Prostrate (to decumbent) ground cover,
white/purple owers
C. arborea Druce South Island broom,
swamp broom, tree broom Shrub or small tree, scented white/purple owers
C. astonii G.Simpson Aston’s dwarf broom Dwarf and spreading ground cover,
white/purple owers
*C. australis R.Br. Common native broom Shrub or small tree, white/purple owers
†C. carmichaeliae (Hook.f.) Heenan Marlborough pink broom Shrub or small tree, slender drooping branchlets,
abundant pink owers
*C. compacta Petrie Cromwell broom Erect or spreading shrub, purple owers
*C. corrugata Colenso Common dwarf broom Dwarf and rhizomatous, purple owers
C. crassicaulis Hook.f.
subsp. crassicaulis Coral broom Robust shrub, grooved branches,
off-white / purple owers
*C. crassicaulis subsp. racemosa
(Kirk) Heenan Slender coral broom Spreading to upright shrub, grooved branches,
off-white / purple owers
*C. curta Petrie Waitaki Broom, whip broom Spreading to sprawling sparsely branched shrub,
purple/white owers
*†C. glabrescens (Petrie) Heenan Marlborough pink broom Shrub or small tree, slender drooping branchlets,
abundant pink owers
*C. hollowayi G.Simpson Holloway’s broom, whaupaku Low-growing shrub,
purple or red purple / white owers
C. juncea Hook.f. (No common name known) Prostrate and sprawling shrub,
owers white with various shades of purple
*C. kirkii Hook.f. Climbing broom, Kirk’s
broom, scrambling broom
Sprawling shrub or climbing vine,
white/purple owers
†C. monroi Hook.f. Stout dwarf broom Dwarf and spreading,
white and pinkish-purple owers
*C. muritai (A.W.Purdie) Heenan Clifford Bay broom,
coastal tree broom
Small tree, upright growth habit,
white/purple-violet owers
*†C. nana (Hook.f.) Hook.f. Dwarf broom Dwarf ground cover, purple
(or rare creamy-white) owers
*†C. odorata Benth. Leafy broom, maukoro,
scented broom Leafy shrub, scented white/purple owers
C. petriei Kirk Desert broom Shrub, white/purple-violet owers
*†C. stevensonii (Cheeseman) Heenan Cord broom,
weeping tree broom
Small tree, weeping stems,
abundant sprays of pale lavender owers
C. torulosa (Kirk) Heenan Canterbury pink broom Small tree or large shrub, pink/purple owers
*C.uniora Kirk Dwarf broom,
single-owered broom
Dwarf and rhizomatous ground cover,
white/purple owers
C. vexillata Heenan Dwarf broom Dwarf and spreading, pinkish purple owers
*†C. williamsii Kirk Giant-owered broom,
William’s broom
Robust shrub, broad and attened cladodes,
creamy-yellow owers
* = currently available from native plant nurseries.
† = particularly recommended for cultivation.
Low-growing brooms
There are nine species of low-growing,
prostrate, decumbent or dwarf native
brooms. Most are restricted to the
eastern South Island. Their low stature
and preference to grow in dry, open
and sunny conditions makes them
ideal for rock gardens, container plants,
or as ground covers on exposed sites.
The tight growing dwarf species are
especially good in rock gardens.
Carmichaelia appressa (appressed
broom, prostrate broom): a species
largely restricted to Kaitorete Spit
near Christchurch, where it grows
on stabilised sand dunes and ridges
(Fig. 2). Although most plants
are protected within a scientic
reserve, they remain vulnerable to
damage by off-road vehicles and
other disturbances. Following the
New Zealand Threat Classication
System, it is classied as an “At Risk
– Naturally Uncommon” species.
C. appressa has yellowy-green
cladodes and white owers streaked
with purple. It is a prostrate shrub that
grows to 25–40 cm tall with a spread
of up to 2 m in the wild, although
0.5(–1) m across is more usual in
cultivation. This species is ideally
suited to rock gardens or retaining
walls where there is good drainage.
Carmichaelia astonii (Aston’s dwarf
broom): a “Threatened – Nationally
Vulnerable” species conned to a
few limestone cliff areas in eastern
Marlborough. This dwarf and spreading
Fig. 2 Carmichaelia appressa growing
wild in the seemingly barren Kaitorete Spit
landscape. Photo: Peter Heenan.

8 New Zealand Garden Journal, 2016, Vol. 19(1)
shrub grows to 20 cm tall (rarely to
50 cm tall for old plants in cultivation)
and up to 50 cm across. This species
has greenish-brown cladodes and
produces an abundance of white
owers streaked with purple. It is easy
to grow and does best in well-drained
soil enriched with added lime in a sunny
position.
Carmichaelia astonii is restricted to
limestone in Marlborough and allied to
C. monroi and C. vexillata. The three
native brooms that are restricted to
limestone habitats (called calcicoles)
are C. astonii, C. glabrescens and
C. hollowayi.
Carmichaelia corrugata
(common dwarf broom): an “At Risk –
Declining” species found on open sandy
gravel river terraces in Marlborough,
Canterbury and Otago. It is very low
growing (only 2–8 cm tall) and forms a
dense mat (up to 1 m across) through
rhizomatous growth. Its cladodes are
yellowish-green with blunt orange tips
and its owers are purple with white and
pink colorations. This is another species
well suited to rock gardens. It is allied to
C.uniora.
Carmichaelia hollowayi
(Holloway’s broom, whaupaku):
this species has the highest threat
classication of “Threatened –
Nationally Critical” as there are less
than 250 adult plants in the wild from
three populations. Like our other
threatened native brooms, browsing by
animals and competition from weeds
are the usual culprits. C. hollowayi is
restricted to limestone outcrops of the
Waitaki River, South Canterbury. This
dwarf and suckering shrub grows to
50 cm tall and 50 cm to 1 m (rarely
up to 2 m) across. It has yellow-green
erect and orange-tipped cladodes
which are quite robust. Its owers are
purple or red purple with white margins.
C. hollowayi has been reported to do
well in cultivation despite its exacting
habitat conditions in the wild.
Carmichaelia juncea: another rarity
(“Threatened – Nationally Vulnerable”)
of the South Island and with a
diminishing range in the wild. It was
collected once from the North Island
but is now presumed extinct there – it
has also apparently disappeared from
Marlborough, Canterbury, Otago and
Southland. Currently, it is only known
from a small area in North-West Nelson
(near Puponga) and in scattered sites
in Westland (from Franz-Josef Glacier
south to near Haast). I remember many
years ago (before current workplace
safety policies!), accompanying my
workmate who was gearing up to
access this species by abseiling off
the main road bridge across Fox River.
When we showed up, the river was
unusually low and we could reach the
plants wearing gumboots. At this site,
C. juncea was growing on an island
formed by forks in the river that usually
prevented herbivores (and humans)
from reaching the population of this
threatened broom. C. juncea has a
sprawling, prostrate growth habit and
forms attened mats up to 20 cm
tall and 1.5 m across. Flowers are
white or with various shades of purple
streaks. In the wild, it grows on river
bed gravels and stony and sandy lake
sides, or on weathered rock in coastal
areas. Because C. juncea is adapted
to exposed conditions, it is well
suited to rock gardens and growing
in containers. C. juncea is related to
C. compacta and C. curta.
Carmichaelia monroi
(stout dwarf broom): classied as
“Not Threatened” but is nevertheless
conned to Marlborough and
Canterbury in the wild where it’s
usually found in open, stony or rocky
habitats adjacent tussock grassland
(Fig. 3A–B). C. monroi is a dwarf
plant (up to 15–25 cm tall) that can
eventually spread up to 1 m across. Its
white and pinkish-purple owers are
relatively large and contrast well with
its dense and attened yellowish-green
cladodes with blunt orange or red tips.
Although rather slow growing it is easy
to cultivate and very well suited to the
rock garden.
A
B
Fig. 3 Carmichaelia monroi growing wild
on a stony slope north of Mt Fyffe, Seaward
Kaikoura Range. A, plant showing typical
heavy browsing. B, close-up of owers.
Photos: Murray Dawson.
Carmichaelia nana (dwarf broom):
an “At Risk – Declining” species found
in scattered locations in the North
Island (Central Volcanic Plateau) and
South Island (Marlborough, Canterbury
and Otago). North Island plants were
previously known as C. orbiculata and
South Island plants as C. enysii, but
in 1995 my colleague Peter Heenan,
as part of his PhD revisions of the
native brooms, accepted a broader
circumscription, reducing both names
to synonyms of C. nana. This species
is usually found in open places, river
terraces and moraines. Plants form
dense, very low-growing mats that only
reach 2–6(–10) cm tall, with a spread
of 10–20(–50) cm across. Its cladodes
are usually erect and densely crowded,
and green or yellow-green in colour.
Although it has relatively small owers,
they are conspicuous and contrast well
with the narrow cladodes. Flowers are
usually purple (Fig. 4A), although rare
creamy-white owered variants have
also been found in the wild (Fig. 4B).
C. nana is easily grown and makes an
attractive and diminutive addition to the
rock garden.
A
B
Fig. 4 Carmichaelia nana. A, plant with typical
coloured owers growing wild at McKenzie
Pass. Photo: Peter Heenan. B, creamy white-
owered variant from Two Thumb Range,
Otago. Photo: Andrew Purdie.
Carmichaelia uniora (dwarf broom,
single-owered broom): an “At Risk –
Declining” dwarf broom found in open
habitats including river beds, terraces
and stony ground.

New Zealand Garden Journal, 2016, Vol. 19(1) 9
This species is restricted to South
Island localities in Nelson, Canterbury,
Otago and Southland. It forms a low-
growing cushion 2–6 cm tall and 30 cm
to 1 m across through rhizomatous
growth. This species has thread-like
and erect cladodes and unless seen
in ower, plants are somewhat hidden
(and can be out-competed) by any
surrounding vegetation. Flowers are
usually solitary (hence the species
name “uniora”), and are white with
purple streaks. It is slow-growing in
cultivation and well suited to rock
gardens. C.uniora is somewhat
similar to C. corrugata.
Carmichaelia vexillata (dwarf
broom): the remaining dwarf broom
is yet another “At Risk – Declining”
species. In 1995 Peter Heenan
recognised this species as new
and segregated it from C. monroi.
C. vexillata is restricted to the eastern
side of the Main Divide of the South
Island, where it occurs in open habitats
including river terraces. It grows to
15 cm tall with a spread of 40 cm
across. Cladodes are yellowish-green
with blunt orange or red tips. Flowers
are pink with purple streaks. Like all of
the dwarf brooms, C. vexillata is easy
to propagate and grow. However, it is
not widely cultivated under that name.
Shrub / small tree brooms
The majority of New Zealand’s
native brooms are shrubs, or at best,
small trees. Some that are found in
cultivation are mentioned in this article.
Carmichaelia australis
(common native broom): called the
“common native broom” because of
its relative abundance. Accordingly,
this species is categorised as “Not
Threatened” and is found wild in both
the North and South Islands (excluding
Otago and Southland), where it
grows in a range of generally open
habitats. This species is a fast growing,
upright to spreading shrub or small
tree (Fig. 5A) which can attain 6 m or
more in height (although 4 m is more
usual in cultivation). The green stems
(cladodes) are attened and there are
scattered true leaves, especially on
shaded plants. Flowers are relatively
small and are white with purple
markings (Fig. 5B). As in other native
brooms, upon maturity the sides of
the seed pod walls fall away to reveal
seeds that hang in the remaining
structure called a replum (Fig. 5C).
A
B
C
Fig. 5 Carmichaelia australis in cultivation.
A, mature shrub growing at Fernglen Native
Plant Garden showing a typical upright habit
with multiple branching from the base.
B, close-up of purple owers (Auckland Botanic
Gardens). C, close-up of open pods, each
containing an orange-red seed with black
mottling (Fernglen Native Plant Garden).
Photos: Murray Dawson.
In 1995, Peter Heenan broadened
the circumscription of C. australis to
reduce more than a dozen species
into synonymy with it. Some of these
previously accepted names persist
in horticulture (e.g., C. arenaria,
C. cunninghamii, C. egmontiana,
C.agelliformis, C. rivulata and
C. robusta).
Carmichaelia carmichaeliae and
C. glabrescens (Marlborough pink
brooms): these two native pink-
owering brooms share similar growth
habits, slender drooping branchlets
and pink owers, but have slightly
different pods. In the wild, both are
conned to steep valley sides and
cliff faces in Marlborough. However,
C. carmichaeliae is the rarer species
(“Threatened – Nationally Critical”)
and found north of the Awatere fault
whereas C. glabrescens is “Not
Threatened” and grows south of the
Awatere fault. Prior to Peter Heenan’s
revision, they were included as species
of Notospartium3.
Both are beautiful shrubs or small trees
that deserve to be much more widely
cultivated. In the wild they can grow
to 5 m (for C. carmichaeliae) and 7 m
(C. glabrescens) or more tall, although
as garden plants they are usually
much smaller. Their habit, foliage and
especially their abundant sprays of
strongly coloured pink owers make
them excellent subjects for planting.
Although C. glabrescens is said to be
difcult to keep growing (which is likely
true in warm and humid climates such
as Auckland), there is a magnicent
30-year old specimen at my workplace
(Landcare Research in Lincoln),
planted by the late Andrew Purdie
(Fig. 6A–D). Andrew provided this
plant with ideal conditions – a raised
limestone rock garden in full sun, with
perfect drainage and no watering.
Carmichaelia compacta (Cromwell
broom): as its common name implies,
this species is restricted (“At Risk –
Naturally Uncommon”) in the wild to
several river gorges in Central Otago
where it grows on loose rocky schist.
The species name “compacta” refers
to its tighter growth form than many
other native shrubby brooms and it
grows 1–2 m tall. Cladodes are yellow-
green and it produces predominantly
purple owers with white markings.
C. compacta is not that common in
cultivation but probably worthy of being
grown more widely.
3 Based on the taxonomic evidence he gathered, Peter decided that the two tree broom genera (that included species in Chordospartium and
Notospartium) and a shrub genus (Corallospartium crassicaulis) did not warrant their separate recognition from Carmichaelia. Consequently,
Peter placed all New Zealand native broom species into the one genus, Carmichaelia.

10 New Zealand Garden Journal, 2016, Vol. 19(1)
A
B
C
D
Fig. 6 Carmichaelia glabrescens cultivated
at Landcare Research, Lincoln. A, plant in
full ower. B, pink owers. C, close-up of
bright pink owers. D, close-up of seed pods.
Photos: Murray Dawson.
Carmichaelia crassicaulis (coral
broom): both subspecies (the “At
Risk – Declining” coral broom, subsp.
crassicaulis, and the “Threatened
– Nationally Vulnerable” slender
coral broom, subsp. racemosa) are
found in the South Island east of the
Main Divide and were previously
placed in Corallospartium. The
common name “coral broom” refers
to the distinctive appearance of these
unusual shrubs that resemble coral
with their parallel grooved branches.
This is most obvious in the more
robust Carmichaelia crassicaulis
subsp. crassicaulis (Fig. 7), which
is taller growing (up to 2 m tall, but
seldom reaching that in the wild due
to browsing). Slender coral broom is
lower growing (up to 1.2 m) and has
a more spreading habit and thinner
branches. Flowers of both subspecies
are cream to pale pink streaked with
purple.
Fig. 7 Carmichaelia crassicaulis subsp.
crassicaulis growing wild in the Mackenzie
Basin. Photo: Andrew Purdie.
This species is occasionally grown
as a novelty or connoisseur plant but
seldom offered for sale.
Carmichaelia odorata (leafy
broom, maukoro, scented broom):
classied as “Not Threatened” and
found in the wild in southern areas
of the North Island and northern and
western areas of the South Island.
As the name “odorata” suggests,
this species (Fig. 8A–C) has sweetly
scented owers. The small owers are
quite showy, being white with purple
veins and produced in abundance
throughout summer. Its common name
“leafy broom” is because it can become
quite leafy over spring and summer,
unlike most of our other native broom
species. This shrub is relatively
compact, growing to 3 m tall (usually
1–2.4 m in cultivation) and is also
quite broad (growing to 2 m across).
These features make it well suited to
cultivation and it can also tolerate light
shade. Selections have been sold
under the cultivar name Carmichaelia
odorata ‘Lilac Bouquet’, but I doubt
they are signicantly different to the
typical species. C. arborea is a similar
species, and is also leafy and with
scented owers.
A
B
C
Fig. 8 Carmichaelia odorata. A, plant in
ower. B, close-up of owers. C, close-up of
mature seed pods. Photos: Peter Heenan.

New Zealand Garden Journal, 2016, Vol. 19(1) 11
Carmichaelia williamsii (giant-
owered broom, William’s broom):
an “At Risk – Relict” species endemic
to the North Island. In the wild, it
is a strictly coastal species known
mainly from northern offshore islands
(particularly the Poor Knights and
Alderman Islands). On the mainland it
is apparently now only known from two
small remnant populations near East
Cape. This distinctive species is the only
New Zealand native broom with creamy-
yellow owers. The owers and seed
pods are comparatively large as are
the broadly attened green branchlets
(cladodes). These robust shrubs can
grow to 4 m tall, but are usually much
shorter in cultivation (1.2–2 m), and
can be trimmed to keep them compact.
Plants can be grown in the open or they
will tolerate light shade. C. williamsii
is likely to do best when planted
in warmer, northern coastal areas.
However, the best plant that I have ever
seen is cultivated far south of its natural
range, in the Larnach Castle grounds
atop the Otago Peninsula (Fig. 9A–E).
The Marlborough tree brooms
Special mention must be made of my
personal favourites – the Marlborough
tree brooms once belonging to the
genus Chordospartium.
Early in my career at the then DSIR
Botany Division (in the 1980s), I had
the privilege of accompanying the late
Andrew Purdie on eld work to study
New Zealand native tree brooms in
Marlborough and Canterbury.
In those days, these tree brooms were
placed in the genera Chordospartium
(a genus restricted to Marlborough)
and Notospartium (conned to inland
Canterbury). Following Andrew’s
untimely death in 1989, Peter Heenan
took on the revision of New Zealand’s
native brooms as the subject of his PhD
studies in the 1990s. As mentioned
previously, as a result of Peter’s
revisions, all New Zealand native broom
species are now placed into the one
genus, Carmichaelia.
Carmichaelia muritai (Clifford
Bay broom, coastal tree broom):
I well remember visiting this then
newly discovered coastal tree broom
growing at Clifford Bay in Marlborough
(which has long been proposed
as an alternative South Island site
to Picton for the inter-island ferry
terminal). Carmichaelia muritai was rst
discovered at this unlikely location in the
early 1980s by Ron Feron4, a Noxious
Plants Ofcer based at Seddon.
In 1985, this outlier tree broom was
described as a separate species
by Andrew Purdie, who named it
Chordospartium muritai (“muritai”
appropriately meaning “sea breeze”
in Mäori), before the species
was subsequently transferred to
Carmichaelia by Peter Heenan. On-
site conservation efforts at the time
comprised of collecting seed from this
remnant population, growing them in
cultivation and planting the seedlings
back out in the wild surrounded by
wire mesh in an attempt to exclude the
hordes of hungry mouths. A second
small population has since been found
at Marfells Beach, to the south of the
Clifford Bay discovery site. However,
this species remains extremely rare
and like its counterpart Carmichaelia
stevensonii, C. muritai is classied as a
“Threatened – Nationally Endangered”
species. C. muritai has an upright,
rather stiff growth habit (up to 6 m
tall) compared to the weeping habit
of C. stevensonii. It produces sprays
of whitish owers with purple-violet
markings (Fig. 10A–B). Although not
as spectacular as C. stevensonii,
C. muritai is easy to grow and worth
cultivating for its rarity value alone.
A
B
Fig. 10 Carmichaelia muritai. A, owers.
B, close-up of owers. Photos: Peter Heenan.
A
B
C
D
E
Fig. 9 Carmichaelia williamsii cultivated
in the South Seas Garden on the Larnach
Castle grounds. A, magnicent architectural
specimen planted in an ideal location.
B, owers and branchlets. C, close-up of a
wide and attened branchlet called a cladode.
D, close-up of distinctive creamy-yellow
owers. E, close-up of seed pod.
Photos: Murray Dawson.
4 Not “Fearon” as spelt by Metcalf 2011, p. 52.
Ron sent plant specimens of his nd to
Andrew Purdie for identication and as
a result I accompanied Andrew on at
least one trip to the eld site. At Clifford
Bay we saw them barely maintaining
their existence, hanging on to steep
eroding coastal cliff faces, sandwiched
between the farmland pasture terraces
above and the coast below. Only 28
mature plants from this one population
were surviving (just), and all accessible
seedlings were being actively browsed
by rabbits and hares.

12 New Zealand Garden Journal, 2016, Vol. 19(1)
Carmichaelia stevensonii (cord
broom, weeping tree broom):
another standout recollection of
my early eld work as a botanist is
spending hours climbing up a steep,
rugged and narrow stream in the
Seaward Kaikoura ranges to reach the
upper catchment – an area completely
inaccessible to the sheep and cattle
that we left behind in the lowlands.
Exhausted from our day of exertions,
Andrew Purdie and I pitched a tent
in the streambed and were heating a
brew at dusk when we had two deer
walk right past our tent before noticing
us! The following morning, after
walking further upstream, we were
greeted by the amazing sight of dozens
of weeping tree brooms growing with
their characteristic straight banded
trunks supporting an umbrella of
cascading cord-like photosynthetic
stems (like many native brooms they
largely lack true leaves). Where we
saw them in this upper catchment, they
were seemingly impossibly growing up
out of rocky ground on exposed slopes
alongside the streambed (Fig. 11).
Fig. 11 Carmichaelia stevensonii growing wild
in the upper George Stream, 900 m asl.
Photo: Peter Heenan.
Like other brooms, C. stevensonii
has hard seed coats that need to be
scaried, in this case, possibly by the
abrasive action of stones as seed are
washed down streams – these are
plants adapted to disturbed habitats.
The weeping tree broom is not
conned to their upper Marlborough
catchments by choice as it was once
found all the way down to the coast.
However, they now have no chance
of establishing downstream with their
seedlings being eaten out by ravenous
herbivores and are out-competed
by lowland weeds of riverbeds. This
species is classied as “Threatened –
Nationally Endangered”.
Carmichaelia stevensonii is one of our
most beautiful native brooms. It is the
tallest tree broom, and can grow to
10 m tall, although 3–5 m is more usual
in cultivation. It has weeping foliage
and cascading racemes of white
owers with purple streaks, giving the
overall impression of pale lavender
coloured owers. In cultivation
(Fig. 12A–D) it makes an excellent
architectural feature tree that I highly
recommend.
A
B
C
D
Fig. 12 Carmichaelia stevensonii planted
at the front of a house in Beckenham,
Christchurch. A, mature tree. B, banded
trunks. C, owers and weeping stems. D,
close-up of lavender coloured owers.
Photos: Murray Dawson.
The climbing broom
There remains one more surprise
amongst all of the diversity found in
our native brooms – the remarkable
climbing broom.
Carmichaelia kirkii (climbing broom,
Kirk’s broom, scrambling broom):
instead of a low-growing plant, or
shrub, or tree, this oddball stands
out as the only climbing species.
C. kirkii (Fig. 13A–B) is a “Threatened
– Nationally Vulnerable” species
restricted to eastern South Island (from
the Awatere River in Marlborough
south to Otago). It is found naturally in
scrubland on river terraces, in wetlands
and native kahikatea or tötara forests.
Its tolerance of poorly drained habitats,
having a reasonable number of leaves
in shaded situations, and especially
its climbing habit is most unusual
compared to our other native broom
species. It has interlacing green to
brownish stems that climb, scramble
or sprawl 1–3 m high. Flowers are
predominantly white with smaller
purple markings and are arranged
in small clusters. This species is not
widely cultivated, but is reported to
do well when given moist ground and
allowed to grow up through a shrub or
over a wall.
A
B
Fig. 13 Carmichaelia kirkii. A, close-up of
clustered owers. B, close-up of mature seed
pods. Photos: Peter Heenan.
Final comments
Amongst the remarkable diversity
of our native broom species proled
here, there is a good range suitable for
cultivation that deserves to be more
widely planted.

New Zealand Garden Journal, 2016, Vol. 19(1) 13
Provided that you meet their growing
requirements, I particularly recommend
(as indicated in Table 1) the dwarf
species such as C. monroi or C. nana
for the rock garden, the bright
pink-owered C. carmichaeliae or
C. glabrescens as a shrub for open
areas, C. odorata for its scented
white and purple owers, C. williamsii
as a bold architectural shrub with
yellow owers, and C. stevensonii as
an outstanding specimen tree with
lavender owers.
Because so many of our native
brooms are threatened in the wild,
growing them in cultivation may
help ensure their survival. Some
of the most threatened species
include Carmichaelia carmichaeliae,
C. hollowayi, C. muritai, C. stevensonii
and C. torulosa.
Ideally, natural habitat restoration in the
wild is the best long term conservation
solution for any threatened species.
Unfortunately, habitat restoration
is difcult for the brooms when
considering their preference for
growing in disturbed habitats and
major issues with weed infestation and
high browsing pressure. Hopefully this
article helps raise awareness of these
unique members of our native ora.
Acknowledgements
I thank Rowan Buxton and the late
Andrew Purdie for their comradeship
and accompanying them in the eld.
Peter Heenan kindly commented on
the draft of this article and provided
his images and Andrew’s photographic
slides for scanning to supplement my
own images for this article.
References
de Lange, P.J.; Heenan, P.B.; Norton,
D.; Rolfe, J.; Sawyer, J. (2010).
Threatened plants of New Zealand.
Canterbury University Press,
Christchurch. 472 pp.
Heenan, P.B. (1995). A taxonomic
revision of Carmichaelia
(Fabaceae–Galegeae) in
New Zealand (part I). New Zealand
Journal of Botany 33: 455 – 475.
Heenan, P.B. (1996). A taxonomic
revision of Carmichaelia
(Fabaceae–Galegeae) in
New Zealand (part II). New
Zealand Journal of Botany 34:
157–177.
Heenan, P.B. (1998). An emended
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with new combinations, a key, and
notes on hybrids. New Zealand
Journal of Botany 36: 53– 63.
Heenan, P.B. and Barkla, J.W. (2007).
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New Zealand trees and shrubs.
Penguin Group (Raupo), Auckland.
408 pp.
Websites (accessed June 2016)
Flora of New Zealand online:
www.nzora.info
Matai Nurseries Ltd:
www.nznatives.co.nz
Naturally Native NZ Plants Ltd:
www.naturallynative.co.nz
New Zealand Plant Conservation
Network: www.nzpcn.org.nz
Oratia Native Plant Nursery:
www.oratianatives.co.nz
Plant proles > Carmichaelia:
www.o2landscapes.com/pages/
pp-carmichaelia.php