Roses
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Roses are without doubt the best known
cultivated flower. However, the style of flower widely recognised as being the
typical rose, the pointed bud of the hybrid tea, is a relatively modern form.
To understand roses we need to look further back.
The history of the rose
Species
Roses have a long and complicated history
but like all plants their development started from the wild species. The genus Rosa contains approximately 100 species, is restricted to the Northern
Hemisphere and is thought to have been in existence for over 30 million years.
Although modern garden roses are highly
developed plants, they are not so far removed from their wild ancestors that we
cannot see the link. The dog rose (R.
canina) and the briar rose (R.
rubignosa) are widely regarded as weeds but they are clearly roses
nevertheless.
The history of the rose has seen many
species used for breeding but relatively few have had a major influence. Modern
roses clearly show the effects of R.
chinensis as this species was most responsible for the multitude of colours
and the repeat flowering of modern roses. The musk rose (R. moschata) and R. gallica
also influenced our modern plants and in recent years gardeners have returned
to the ‘old rose’ style that these plants typify. The evergreen tendencies and
healthy foliage of modern roses is often due to the Japanese species, R. rugosa. Other species that have also
made their mark include R. kokanica
and R. wichuraiana.
Most of our garden roses are hybrids but
some species are cultivated. The banksia rose (R. banksiae), a Chinese
native with a brief but spectacular flowering season, is probably the best
known. It is a near-thornless climber that can grow to 10 m × 10 m
and is most commonly seen in its double forms, ‘Lutea’ (yellow) and ‘Alba Plena’
(white). Rosa rugosa and R. chinensis forms, such as the two-tone pink and yellow
‘Mutabilis’ are also widely grown.
Roses enter cultivation
The use of wild roses for the production
of rosewater, scented oils and other fragrances goes back to the Sumerian
civilisation of Iraq around 2000 BC. Deliberate cultivation of roses also goes back a
long way: Confucius (551-479 BC) mentions extensive plantings in the Chinese
Imperial gardens and there is evidence of well-established cultivars by 100 BC.
Undoubtedly the Romans and other early European civilisations also grew large
quantities for commercial use.
Early cultivars
The early European garden roses were
probably forms of R. gallica, a
native of Europe from France to the Caucasus. Gallicas are usually compact plants with fragrant flowers in a
variety of shades from white through pink to red (including bicolours) and in
all forms from single to very full doubles.
Among the first was ‘Officianalis’, a pink semi-double which was introduced into
France from the Middle East by 13th century crusaders. ‘Versicolor’ or ‘Rosa Mundi’ is a pink
and white-flowered sport of ‘Officianalis’ that dates
from around 1580. ‘Charles de Mills’, a deep wine red double, with very
distinctive flat, circular flowers is currently among the most popular of the
gallicas.
The damask roses (R. gallica × R. moschata
and R. gallica × R. phoenicea) and the bicolour form known as the yellow rose of
Asia (thought to be a form of R kokanica though
usually listed as R. foetida) are
generally regarded as the ancestors of most of the early European roses. The
significance of the yellow rose of Asia lies in its colour — there are no deep
yellow roses native to Europe — and the fact that it readily produced bicolour
yellow and red forms.
There are two basic forms, the summer
damask (R. gallica × R. phoenicea [R. × damascena]) and the autumn damask (R. gallica × R. moschata [R. × damascena
semperflorens]). The summer damask has a well-defined spring and early
summer flowering season while the autumn damask continues blooming sporadically
into autumn. This remontant (recurring flowering) habit was a feature lacking
in many early roses.
The Damask roses are extremely important
in the development of the rose because of their fragrance, a tendency to
produce double flowers and because their flowering season extends into autumn.
These characteristics laid down the pattern for our expectations of roses.
What’s more R. moschata, one of the
parents of the Damask roses, is a climber.
‘Trigintipetala’ or ‘Kazanlik’ was among
the very first damasks. The name means thirty petalled and this 2 m × 2 m plant with strongly
scented, mid pink, loosely double flowers has long been grown for the
production of attar of roses. Among the damasks most widely grown in modern
gardens are ‘Ispahan’, a fragrant, soft mid pink double raised before 1832;
Omar Khayyam, a strongly fragrant mid pink double dating from 1893; The
original pink autumn damask, which is known as ‘Quatre Saisons’; and
‘Versicolor’ or ‘York and Lancaster’, which has loosely double variable pink
and white flowers and has been in cultivation since before 1551.
Another species, R. alba, thought to be the white rose of York of the Wars of
the Roses, is also important in the development of the rose because it was
crossed with the existing gallicas and damasks and produced very scented
flowers. It is of a plant of uncertain origin that may have been introduced to Britain
by the Romans. R. alba
was originally regarded as a variable species, but is now thought to be a
small collection of hybrids of probable R.
mollis × R. gallica parentage.
The centifolia or cabbage roses were the
next development. As with the alba roses the
exceptionally full double (centifolia: one hundred petalled) cabbage rose has
at times been regarded as a species (R.
centifolia), although it is now though to be a hybrid between the Autumn
Damask and an Alba. Centifolias are usually compact bushes and their flowers
are so fully double and heavy with petals that they often droop under their own
weight.
‘Cristata’ (‘Chapeau de Napoléon’ or
‘Crested Moss’) is one of the most popular centifolias. It has fragrant, mid
pink, double flowers, the buds of which are covered in fine tubercles or
filaments known as moss. Mosses are natural mutations that first occurred on
Damask and Centifolia roses. They were very fashionable in the eighteenth and
early nineteenth centuries and several hundred forms were raised. Some, such as
very deep blackish-red-flowered ‘Nuits de Young’ are still grown today.
The China rose arrives
Other developments of the damask rose,
such as the Portland roses, tended to be obscured by major developments in the late 18th
and early 19th centuries. At this time, roses, like many other large genera,
saw an enormous change in their development as plant hunters started to send
back material from China.
Perpetual flowering semi-dwarf bushes
were cultivated in China well before the start of European rose
breeding. The parent of many of these, R.
chinensis, was introduced around 1752 followed by some hybrids (probably R. chinensis × R. × odorata) in 1792.
China roses, as these early hybrids are known, are still available. Among
the most commonly grown are ‘Cramoisi Supérieur’, a small shrub with deep red
semi-double to double flowers that is also available in a climbing form and
‘Old Blush’, a fragrant mid pink semi-double that was among the first
introductions, again also available as a climber.
Bourbon roses originated from a chance
natural hybridising between R. chinensis
and an autumn damask on the once important French outpost of the Île de Bourbon
— now known as Réunion — an island between Madagascar and Mauritius. Seed of the original plant was sent to France
and crossed with gallicas and damasks to produce the first Bourbons. These
plants, which are long blooming and strongly scented, are still widely grown.
‘Souvenir de la Malmaison’ (pale pink, double) and ‘Zephirine Drouhin’ (deep
pink, double) are among the most popular.
Noisette roses were the first hybrid
group to originate from the United States. They result from hybrids of R.
moschata × ‘Parson’s Pink China’. They are generally strong growing bushes
or climbers with clusters of fairly small flowers in pastel shades of yellow or
pink. Noisette climbers have recently become very popular and many nurseries
now stock them. Among the most commonly available are: ‘Alister Stella Gray’, a
light golden-yellow, fragrant double; ‘Desprez à Fleur Jaune’, which has pink
buds opening to soft golden-yellow, scented, double flowers; ‘Lamarque’ (‘Thé
Maréchal’), fragrant double, pale yellow flowers that age to creamy white: and
‘Mme Alfred Carrière’, which has large white-blushed-pink double flowers.
Tea roses or tea-scented roses are
another development of R. chinensis. These plants, which flower in shades of
white pink and yellow, are hybrids of R.
gigantea × R. chinensis, a cross
known as R. × odorata. They enjoyed a
period of popularity around the 1830s, but the real significance of the tea
rose to modern gardeners is that it was crossed with the other styles to
produce the hybrid perpetual roses, which were the direct predecessors of the
modern hybrid teas.
Hybrid perpetuals were by far the most
popular garden roses of the 19th century. They were originally introduced in
1835 and enjoyed about 70 years of immense popularity. A few are still grown
but they are now something of a novelty. Hybrid Perpetuals often have very
large, strongly scented flowers but they are seldom tidy growers. Few nurseries
stock many hybrid perpetuals but you may see ‘Empéreur du Maroc’, which has
small, highly scented, deep purplish-red flowers; ‘Général Jacqueminot’
(‘General Jack’), a fragrant, deep cerise-tinted-red double; and ‘Prince
Camille de Rohan’, which has deep purplish-red, fragrant, double flowers.
Modern roses
The hybrid perpetual roses were strong,
health plants that made the tea roses appear rather weak and spindly, but tea
roses had beautifully shaped buds and flowers in shades of soft yellow that
were lacking in the hybrid perpetuals. It was an obvious move to cross the two
and in 1867 the first hybrid tea, ‘La France’,
a soft pink double, appeared.
‘La France’ was followed by further pinks
and some pale yellows, but a lack of bright colours meant that hybrid teas did
not appear to offer any great improvements over existing forms and they did not
cause any great excitement initially. It wasn’t until the bright yellow,
double-flowered Rosa foetida var. persiana was introduced into the breeding programme by the French
breeder Pernet-Ducher that hybrid teas started to become the dominant roses.
His first bright yellow, ‘Soleil d’Or’ was exhibited in 1898.
Unfortunately the early hybrid teas were
rather tender for European gardens and in many areas had to be protected over
winter. This was remedied by the introduction of R. wichuraiana into the recipe in the mid 1940s and most of our
modern hardy hybrid teas date from after this period.
There are hundreds of hybrid tea roses to
choose from and most of them are very heavy flowering and have large blooms on
long stems that are ideal for picking. Which to choose is largely a matter of
personal preference and what best suits your garden. Among the most popular
are:
‘Alexander’ (1972)
A strongly upright bush
(2 m × 1.8 m) with vivid vermilion orange double flowers.
‘Aotearoa NZ’ (1990)
A dense compact bush (1.5 m ×
1.2 m) with very fragrant, soft pink, double flowers.
‘Auckland Metro’ (1988)
A vigorous bush
(1.5 m × 1.5 m) with good foliage and slightly fragrant, creamy
white, double flowers.
‘Big Purple’ (1987)
A strong, healthy bush (1.5 m ×
1.2 m) with large, fragrant, deep reddish-purple, double flowers.
‘Deep Secret’ (1977)
A dense bush (1.5 m × 1.2 m)
with reddish foliage and very dark red, fragrant, double flowers.
‘Double Delight’ (1977)
A compact bush
(1.2 m × 1 m) with slightly fragrant, cream-edged-carmine, double
flowers.
‘Fragrant Cloud’ (1967)
A vigorous but compact
bush (1.5 m × 1 m) with strongly scented, orange-red fading to coral,
double flowers.
‘Gold Medal’ (1982)
An upright bush
(1.8 m × 1.5 m) with deep golden-yellow buds that open to bright
yellow double flowers.
‘Ingrid Bergman’ (1986)
An upright bush 1.5 m × 1 m)
with deep red double flowers that last well when cut.
‘Loving Memory’ (1981)
A dense bush
(1.5 m × 1m) with large, fragrant, deep red double flowers on long stems.
‘Peace’ (1945)
A dense bush
(1.5 m × 1 m) with large and beautifully formed, soft
yellow-edged-pink, slightly fragrant, double flowers.
‘Solitaire’ (1987)
A strong bush
(1.5 m × 1.2 m) with slightly fragrant, deep yellow-edged-orange-pink,
double flowers.
‘Whisky’ (‘Whisky Mac’ 1967)
A compact bush
(1.5 m × 1 m) with fragrant soft orange-apricot semi-double to double
flowers.
About the same time as the first hybrid
teas were appearing, the polyantha roses were introduced. These compact plants
bear their small flowers in large clusters and were produced by crossing dwarf
forms of R. multiflora with either a
dwarf China or a small hybrid tea. Polyanthas have continued to be grown and
new introductions appear occasionally. Some of the best are: ‘Cecile Brunner’,
which has small pale pink double flowers and is also available as a climber;
‘Perle d’Or’, a somewhat rangy grower with buff-pink double flowers;
‘Strawberry Ice’, which is a dense compact bush with white-edged-cerise double flowers;
and ‘The Fairy’, a mid pink double that can be grown as a bush or miniature
climber.
The polyanthas were very successful
roses, but their flowers tended to be very small and poorly formed. The logical
step was to cross polyanthas with hybrid teas and by so doing, the Danish
Poulsen produced the first floribundas. Floribunda roses are compact and heavy
flowering, with several blooms per stem. As cut flowers they cannot compete
with the hybrid teas but for sheer colour they are hard to beat. Among the best
are:
‘Burma
Star’ (1974)
A strong, stocky bush (1.2 m ×
1 m) with slightly fragrant, golden-yellow buds opening to soft buff,
double flowers.
‘City of Belfast’ (1968)
A very compact bush
(80 cm × 80 cm) with bright red double flowers.
‘Colour Break’ (‘Brown Velvet’ 1983)
A small to medium sized
bush (1 m × 1 m) with unusual rusty orange-brown double flowers.
‘Friesia’ (‘Sunsprite’ 1974)
A dense bush
(1.2 m × 1 m) with brilliant intense yellow, fragrant, double flowers.
‘Iceberg’ (1958)
A vigorous bush (1.5 m
× 1 m) with masses of semi-double white flowers. It is also available as a climber.
‘Margaret Merril’ (1977)
A compact bush
(1 m × 1 m) with strongly scented pure white semi-double to double
flowers.
‘Playboy’ (1976)
A compact bush
(1.2 m × 1 m) with intense orange single to semi-double flowers with
deep golden-yellow centres.
‘Regensberg’ (‘Buffalo Bill’
1979)
A densely foliaged
small bush (80 m × 80 cm) with pink-edged-and-reversed white,
semi-double flowers.
‘Sexy Rexy’ (1984)
A compact bush
(1.2 m × 1 m) with masses of light pink double flowers.
‘Trumpeter’ (1977)
A compact bush (80 cm × 80 cm)
with massed brilliant red, double flowers.
‘Westerland’ (1969)
An upright bush
(1.8 m × 1.5 m) with fragrant, soft orange semi-double flowers with
golden yellow reverse.
Climbing roses
Climbing or strongly upright bushes have
been common over the centuries over rose breeding. Some species, such as R. gigantea and R. filipes are natural climbers and these
plants have been used to produce a few garden plants. But the majority of
garden climbers are really strongly upright bushes that are tied to fences,
pillars or pergola to create the effect of a climber. Ramblers are climbing
roses that produce very strong growth from the base. Some of the best garden
climbers are:
‘Albertine’ (1921)
An extremely vigorous
6 m × 4 m plant with fragrant, soft pink double flowers. It flowers briefly but spectacularly.
‘Birthday Present’
A fairly compact (3 m × 3 m)
climber with strongly fragrant, deep red, double flowers.
‘Compassion’ (1973)
A 3.5 m ×
2.5 m climber that may be grown as a shrub.
It has fragrant apricot-pink double flowers.
‘Dublin Bay’
(1976)
A 2.5 m × 3 m
climber that may be grown as a large shrub. It
has masses of bright red double flowers.
‘Ena Harkness’ (1954)
A 3 m × 3 m
climbing sport of the bush of the same name. It
has fragrant deep red double flowers.
‘Handel’ (1965)
A medium-sized (3 m × 3 m)
climber with white, flushed and edged deep pink, double flowers.
‘New Dawn’ (1930)
A vigorous 4 m × 4 m climber with fragrant, pale pink, loosely double flowers.
‘Veilchenblau’ (1909)
A wiry-stemmed 4 m × 3 m climber with fragrant semi-double greyish-purple flowers that have
occasional white streaks.
‘Wedding Day’ (1950)
A very vigorous 8 m × 5 m plant with massed, fragrant, white, single flowers. It has a short flowering season but produces an amazing weight of
bloom.
Other styles of modern roses
Several rose breeders have developed
roses that are quite different from hybrid teas and floribundas. Some. like the hybrid musk roses (a
cross between a hybrid tea and the musk rose), have been developments or side
branches of the development of hybrid teas and floribundas, but others, such as
the Kordesii roses (R. rugosa × R. wichuraiana), are completely new styles.
Miniature roses are a style that can be
traced back to the small China rose, R.
chinensis ‘Minima’, particularly the form ‘Roulettii’. This is an old form
but it is only in recent years that miniatures have become very popular as new
colours and styles have been produced by crossing the old forms with R. wichuraiana and some of the smaller floribundas.
Not all miniature roses are small bushes.
They all have small flowers but many of the bushes may reach 60-80 cm or more
with time. Some forms are budded onto vigorous bush rootstocks to produce
‘patio roses’. Others are budded onto tall stems to produce miniature standards
and weeping standards.
Ground cover roses are an increasingly
important group that has been produced from a wide range of breeding stock.
These include unusual species, such as R.
sempervirens, R. bracteata and R.
californica, as well as the more common
R. wichuraiana and the various hybrid groups. Most are extremely vigorous
plants capable of carpeting a wide area and many are similar in flower and foliage
to miniature roses.
Old roses and modern roses
Although for many years hybrid teas and
floribunda were the predominant rose types, old roses are now enjoying a
revival. But what is an old rose? Strictly speaking old roses are those that
were in cultivation before 1867 when ‘La France’,
the first hybrid tea, was produced. But much of the recent interest in old
roses can be traced to the English roses raised by David Austin. By crossing
Gallicas, Damasks and Centifolias among themselves and with Floribundas and
Hybrid Teas it has been possible to produce the flower form and scent of the
old roses on compact vigorous bushes that flower throughout the season.
Among the most popular of the English
roses are: ‘Abraham Darby’, an upright bush with fragrant, apricot-pink tinted
yellow, double flowers; ‘Charles Austin’, which has strongly fragrant, soft
buff-yellow, double flowers; ‘Constance Spry’, a semi-climber with strongly
fragrant soft pink double flowers; ‘Gertrude Jekyll’, which is inclined to be a
poor grower but has very fragrant, bright pink, double flowers; ‘Graham
Thomas’, a stocky bush with very fragrant deep yellow double flowers;
‘Heritage’, fragrant, pale pink fully double flowers; ‘Mary Rose’ a compact
bush with very fragrant, deep pink, double flowers; and ‘Othello’, a
medium-sized bush with fragrant, deep wine-red, centifolia style flowers.
Landscaping with roses
Roses are versatile plants that should
not be grown for their flowers alone. There is now such a wide range of roses
in all manner of colours, shapes and growth forms that they can be made to
perform almost any landscaping function in any style of garden.
Over the years it has become something of
a tradition to grow roses separately from other plants. There are advantages in
this because it simplifies the soil preparation and care of the plants, and a
concentration of roses can provide unrivalled colour and fragrance, but it does
tend to lead to unnecessary segregation and division within the garden. Also,
few of us now have enough room in our gardens to devote large areas to just one
type of plant.
Fortunately roses are easily integrated
into the overall garden design. The smaller types, particularly the miniatures
can be planted with other shrubs to provide splashes of colour and they also
blend very well with perennials and annuals. They can also be used as informal
hedges along pathways or for edging larger beds. Ground cover roses can be used
to carpet sloping ground or for cascading over retaining walls. Climbers are
most often used on fences but the more vigorous growers are perfectly capable
of covering an unsightly shed or old tree and when grown over an entrance arch
or French doors they provide a fragrant greeting for visitors to the garden or
house. Roses of graduated heights are very effective for edging garden steps
and for making a smooth transition between low borders and taller shrubs or
trees. Strongly upright roses, such as ‘Queen Elizabeth’ can even be used for
hedging. Be adventurous with your roses because few plants offer so many
choices or have the ability to reward your efforts with so much
colour over such a long season.
Regardless of whether your garden is the
height of formality or completely casual, roses should be an integral part.
They lend themselves to formal planting in rows, large beds and carefully
colour-coordinated borders or they can just be dotted about and left to look
after themselves. There are also roses that can be used for specimen planting.
Weeping miniature standards, for example, often look at their best when out in
the open where their form is uncluttered by other plants.
Colour
Your choice of colours and how you use
them is very much a personal matter. Many gardeners like to coordinate their
colour schemes while others feel that all roses compliment one another.
Solid blocks of colour can often be more
effective than mixed colours, particularly in small areas. Many gardeners try
to plant as many varieties as possible and tend to end up with an ill-matched
assortment. Concentrating of three of four main varieties is generally
preferable in small garden.
Whatever your preference, you will need
to plant your roses where they can be seen at their best. It probably goes
without saying that brick red roses don’t go well with red bricks, but consider
also that deep red roses often fail to stand out against a background of
greenery and that pale pink roses can loose all their colour when grown against
a white wall. Also, remember that roses vary in their length of flowering
season and you will need to position them accordingly.
Container growing
Roses grow well in containers provided
they are regularly fed and do not dry out. Planting roses in containers also
has several advantages: the containers can be moved to where the flowers or
fragrance will be most useful, they can be moved out of view when not in
flower, and container roses can be an effective replacement for cut flowers
indoors. Also, containers are often the only way to grow roses in very small
gardens.
Small bushes, such as floribundas, polyanthas
and miniatures are the styles best suited to container cultivation. Depending
on the size of the plant they can be grown in anything from a small window box
to an urn. Large roses can be grown in half-barrels or other large containers
but they can be rather bare at the base. Smaller bushes tend to have more
foliage and flower more heavily in relation to their size.
Miniature climbers and trailers are also
suitable, but they will need some support and training to shape. Roses like
‘The Fairy’, which can be encouraged to climb and trail, usually look the most
effective as they add height while also spilling over the sides of the
container.
Deep containers should have additional
drainage material, such as gravel or horticultural charcoal, added before filling.
This will ensure the
soil does not become wet or poorly oxygenated at the base of the container. Use
a good potting mix and add a little extra fertiliser to encourage quick root
development. Bark- and soil-based potting mixes are usually preferable to
peat-based mixes, which can become somewhat soggy.
Cultivation
Layout
Before you prepare the ground or plant
your roses consider the practicalities involved. You will need to make sure
that large growers do not overshadow smaller plants, that there is adequate
ventilation between the plants and that there is easy access for pruning and
spraying.
As a rule you can reckon on a rose bush
having a spread that it at least two-thirds of its height. This is important
not just in working out the spacing but in ensuring that the roses do not
encroach too far over paths or lawns.
Siting
Roses require a position that receives
about six hours sun per day; is well ventilated without being exposed to strong
winds; has slightly acid, moisture retentive yet well-drained soil; and which
is free from any excessively competitive large shrubs and trees.
Roses that are too shaded will tend to
become drawn and flower poorly. They will also be more likely to suffer from
fungal diseases. Roses in too windy a site will become damaged and their
flowers will quickly burn, while poor ventilation is sure to lead to fungal
diseases.
Soil preparation
Ideally the planting site should be
prepared well in advance. Roses are heavy feeders so incorporate as much
organic matter and well-rotted manure as possible but don’t add strong chemical
fertilisers at this stage. It is important that the roses establish well in
their first season and too much top growth may stress the young root system and
will almost certainly lead to the production of foliage at the expense of
flowers. Also, long , soft stems are very prone to
wind damage. Stick to mild slow acting fertilisers until the plants are firmly
settled in.
Planting
Look at the main stem of the bush, you
should be able to see a change in colour that shows the level at which the bush
was planted in the field. It should be at about the point of the bud union, this is the level it should be in your garden. If you
bought bare rooted plants, soak them in a bucket of water (possibly with dilute
fungicide added) for several hours, this will ease them over their transplant
shock.
Don’t just dig a hole large enough to
accommodate the plant. Make sure there is good depth and spread of loosened
soil so the root system can quickly develop. Space the plants to allow enough
room for easy access when pruning.
The following are basic planting
instructions:
* If you haven’t prepared the soil in advance work in plenty of compost material at planting time.
* Dig a hole at least twice as wide and deep as the current root spread.
* Plant at the same depth as the rose was growing in the nursery field, look for a change in colour on the main stem that indicates this depth. If you can’t see a mark plant with the bud union just above the soil surface.
* Refill the hole to a depth that will allow the rose to be planted at the right depth. Mound up a cone of soil at the base of the hole and spread the roots evenly over around the cone.
* Fill the hole firming the soil into place as you go. Do not tamp the soil down hard or you will destroy your previous efforts to loosen it. Just firm enough to hold the plant.
* Routinely stake standards and tall bushes to avoid damage from wind rock.
Pruning
There main reasons for pruning are to
promote strong new growth that rejuvenates the bush; to produce a well-shaped
plant; to maintain plant health through improved ventilation, which reduces
fungus problems; and to allow light to penetrate to the centre of the bush,
which promotes even growth.
How far to cut back? You can find all
sorts of theories about how hard to cut back and why but it all comes down to
the initial reasons for pruning; renewing vigour, maintaining health and
shaping. Hard pruning tends to promote strong stems with fewer but better
blooms while leaving longer stems promotes dense bushy growth with many but
smaller blooms.
Consider the ultimate shape of the plant
before you cut. Most bush roses are best grown in a vase shape: a clear centre
with outward growing branches. The branches will tend to shoot from the bud
immediately below a cut, so if the centre of the bush is to remain open you
must cut to buds that face away from the centre of the bush. These are known as
outward facing buds.
When pruning bush roses, look for strong
branches of the previous year’s wood, these will normally have smooth reddish
green bark. Having identified these main stems completely remove
any old, diseased or spindly branches. Then take out any overlapping branches,
water-shoots and basal suckers so that just the main stems remain.
Cut each main branch back to the first
outward facing bud, then look at the shape of the
bush. Is it going to be the shape you want? If not, trim back to lower outward
facing buds. Does it have too many main branches? If so, thin out some of the
branches, you really only need four or five main stems. Is it still too tall?
If so, simply cut back to lower outward facing buds.
Repeat flowering climbers can be pruned
in much the same manner as bushes, but you may wish to leave some inward facing
buds to fill out the structure. Also when vigorous water-shoots are produced it
is better to use them to fill out the plant’s growth rather than cut them back.
Once-flowering climbers and ramblers tend
to flower on lateral growth off the old wood. You will almost certainly have to
trim them to reduce their growth but cutting back too hard will severely reduce
their flowering. The objective is to encourage side shoots, which will flower
and can then be encouraged to grow out sideways to produce more flowering side
shoots.
Always spray with a fungicide after
pruning. You may well have disturbed fungal spores that will find an easy entry
to the plant by way of the freshly cut stems. Also remove all pieces of debris.
There is no point in leaving diseased material lying around to infect your
plants.
Roses are normally pruned in winter
because that is when the plants are dormant and the branch structure is most
easily seen, but there is no reason why you shouldn’t trim and thin in summer
if you wish. Miniature and ground cover roses generally have masses of fine
twiggy stems so careful trimming is impractical. With these types of roses
summer pruning is usually the best option and is just a matter of removing old
or damaged wood and trimming to shape.
Pests and diseases
Roses have an unfortunate reputation for
being prone to pests and diseases. In reality they are not they are not really
that much more affected than any other plants, but the pests and diseases that
attack roses spread rapidly and quickly become very obvious. The key is early
control because if you allow the problem to become established it can be very
difficult to combat.
The number one pest is aphids. They can
strike at any time from the first flush of spring growth till the last leaf
falls in autumn, and in mild areas they may even carry on through winter. There
are many different kinds of aphids, but they all feed by sucking the sap.
Aphids reduce a plant’s vigour and can aid in the spread of viruses. Aphids are
easily killed, even soapy water or regular hosing off will control them but they
have the advantage of numbers: you can knock them back but you can’t wipe them
out.
Thrips and mites are also common rose
pests. Both debilitate the plants through sap sucking and cause mottling of the
foliage. Thrips and the European two-spotted mite are generally found on the
underside of the leaves while the red spider mite can often be seen moving
around, especially on hot days. Refer to the pests and diseases chapter for
control of these and less common pests.
In the long run fungal diseases cause are more likely to cause lasting damage than any
insect pests. The most common rose diseases are mildew (powdery and downy),
blackspot, rust and botrytis.
Botrytis is only really a problem if you
leave the old flowers to rot on the bush, in which case it may lead to
die-back. Regular dead-heading eliminates this potential problem. Mildews lead
to premature foliage drop and general debilitation; blackspot has a similar
effect and is very unsightly. Rust is the worst of the fungal diseases. It
spreads rapidly, can cause almost total defoliation if allowed to take hold,
and may be carried over to the following season if not treated. Again, refer to
the pests and diseases chapter for control methods.
Good ventilation and avoiding
overcrowding will go a long way to preventing fungus problems as will regular
feeding, watering and soil conditioning. Healthy plants grown under good
conditions are far less likely to suffer from pests and diseases and are more
able to cope with them if the are attacked.
Propagation
Most of the roses sold in garden centres
and nurseries have been budded onto vigorous, disease-resistant, non-suckering
rootstocks. Budding roses is not difficult but good rootstocks are not always
generally available to the public.
Roses can also be grown from cuttings
although some modern varieties do not grow well on their own roots and
suckering varieties can become nuisances. Roses will grow from hardwood or
semi-ripe cuttings. Refer to the propagation chapter for details of these
methods.
Growing roses from seed is generally
restricted to species or raising new hybrids. The seed germinates well but it
must be stratified for 8–12 weeks before sowing.
Copyright Geoff Bryant
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