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This is a large ornamental shrub with a fairly long flowering time,
producing large flowers, varying in colour from creamy-green through
silvery pink to deep carmine. A 'beard' of purple-black to pure
white hairs sets off the colour of the inner bracts. Protea neriifolia
is an excellent plant for the garden and an outstanding and long
lasting cut flower.
Protea neriifolia is part of an ancient plant family, the
Proteaceae, which had already divided into two subfamilies before
the break-up of the Gondwanaland continent about 140 million years
ago. Both the Proteoideae and the Grevilleoideae occur mainly in
the southern hemisphere. In southern Africa there are about 360
species, of which more than 330 species are confined to the Cape
Floral Kingdom, between Nieuwoudtville in the northwest and Grahamstown
in the east. Protea neriifolia belongs to the genus Protea,
which has more than 92 species, subspecies and varieties. Other
well-known genera of the Proteaceae are: Leucospermum, known
as pincushions because of their brightly coloured flowers, Leucadendron,
the conebushes, with yellow or red-brown foliage and Serruria,
of which Serruria florida, the blushing bride, is the most
famous, its pale pink flowers making it much sought after for bridal
bouquets.
The
amazing variety in the size and habit of the plants, and in the
size, colour and shape of the flowers of the genus Protea
was the reason it was named after the Greek god Proteus, who could
change his shape at will. The leaves of Protea neriifolia
are most often bright- or dark green and look quite like the leaves
of the oleander (Nerium oleander). This accounts for the
species name neriifolia, which means 'with leaves resembling
those of the oleander'.
Protea neriifolia was first discovered in 1597, was illustrated
in 1605, and has the distinction of being the first protea ever
to be mentioned in botanical literature. It took quite a while before
it was officially recognised as a distinct species by the botanists
and it was only described and named in 1810. Enthusiastic horticulturists
in the meantime had already succeeded in growing Protea neriifolia
in glasshouses in Europe and in 1811 an illustration of a plant
grown to flowering size in the Herrenhaus Gardens near Hanover,
Germany, was published. During the early nineteenth century it was
possible to buy cream or pink flowering plants from a nursery in
England and Protea neriifolia could be found in many private
collections.
Protea neriifolia is a very widespread species and occurs
from sea-level to 1300 m altitude in the southern coastal mountain
ranges from just east of Cape Town to Port Elizabeth. It grows mainly
on soils derived from Table Mountain Sandstone, often in large stands.
The
variability in altitude and locality has led to a wide variation
in both flower colour and flowering time. The flowering time is
between February and November with the plants in the western part
of the range flowering during autumn and winter (February to July),
and the plants in the eastern range flowering during spring and
early summer (August to November). These characteristics are quite
stable and this provides commercial growers with a wide choice for
their particular markets. The 'flowers' of Protea neriifolia
are actually flower heads with a collection of flowers in the
centre, surrounded by large colourful bracts. The flowers are pollinated
by scarab beetles, protea beetles and many other insects, as well
as by birds. The birds are attracted by both the nectar and the
insects visiting the flowers.
Growing Protea neriifolia
In cultivation Protea neriifolia has a wider tolerance than
most other proteas and can be grown in a climate with wet winters
and dry summers, as well as in a climate with dry cold winters and
wet summers, even withstanding light, but brief frosts. The shrubs
are quite fast growing and can reach a height of 1,5 m in about
five years from seed, eventually reaching a height of 3 to 5 metres
and living for 15 years or more. Seed grown plants are generally
about four or five years old before they flower and the plants tolerate,
even benefit from having their flowers cut off every year. Older
plants can get woody and unattractive, with quite short side shoots,
so to keep a plant in shape and to encourage the development of
new shoots and long stems, the stems bearing old flower heads should
be cut back.
Protea neriifolia can be propagated from seed or from cuttings.
Good colour forms or cultivars have to be propagated from cuttings.
Cuttings are made from semi-hardwood, 6-10 cm long, of the current
season's growth, in autumn or spring. The cuttings are dipped for
about four seconds in a rooting hormone solution and placed in a
growing house with bottom heat (25ºC) and intermittent mist.
The rooted cuttings are potted up when the roots are well developed
and planted out in the late autumn in South Africa, or in spring
in colder areas.
The large furry nut-like seeds have to be treated during storage
or prior to sowing with a systemic fungicide like Apron, (active
ingredient metalaxyl) and sown from the middle of March, when the
day temperature starts to drop. The seed is sown in open seedbeds,
in a light, well drained soil and covered with a layer of sand (about
1 cm or 1½ times the size of the seed). The bed is then covered
with a grid against the attacks from birds and rodents. The seed
will germinate three to four weeks after sowing.
Protea neriifolia has quite hard, leathery leaves, which
protect it against most insect attacks and not much damage to the
leaves is visible, except from leaf borers. Like all other proteas,
the most harmful and destructive diseases are fungal. Most losses
occur during the summer months when a virulent root fungus, Phytophthora,
can attack the plants. Control through the use of fungicides in
the garden is difficult and expensive. By the time the plant shows
distress, it is normally too late to arrest the problem. The best
methods of control are cultural, i.e. water the plants early in
the morning; keep the soil surface cool by mulching; remove diseased
plants immediately; do not overwater in summer and prune and remove
diseased material.
Protea neriifolia occurs in fire prone vegetation, where
natural fires occur every ten to thirty years. This 'Mediterranean'
type of vegetation grows in soils with very low amounts of nutrients.
These nutrients are used up by the plants during their lifetime
and need to be returned to the soil to provide the food for a new
generation of plants. Protea neriifolia is adapted to survive
the fires by keeping its seeds safely in the old seedheads, which
will only be stimulated to open and release the seeds when the plant
dies or is killed by fire. These natural fires occur mainly in late
summer or autumn and are followed by the first winter rains, which
provide the moisture the young seedlings need to grow to a size
at which they can survive the long, hot summer.
Books to read:
The Proteas of Southern Africa by J.P. Rourke.
South Africa's Proteaceae by Marie Vogts.
Sasol Proteas, a field guide to the Proteas of Southern Africa by
Tony Rebelo.
The Protea Growers Handbook by Lewis Matthews.
H.G. Jamieson
Kirstenbosch National Botanical Garden
July 2001
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