Cornus: a plant for all seasons

Perhaps best known for their dazzling displays of brightly-coloured stems in winter, bringing warm highlights to gardens when little else is on display, cornus have a great deal more to offer throughout the seasons. Early summer flowers, autumn berries and spectacular autumn leaf colour are among the other gifts they bestow.  They’re also providers of riches for wildlife. The berries are eaten by finches, thrushes and mammals and the starry flowers of several species are popular with pollinators. Flower buds support caterpillars of the holly blue butterfly and the leaves of Cornus sanguinea and others are foodplants for the caterpillars of moths such as the emperor and small angle shades.

These deciduous shrubs and small trees are mostly hardy to at least -10 to -15 degrees C and thrive in full sun or part shade, although they generally produce better flowers, stem colour and leaf variegation in sunny spots. Autumn is a good time to plant, allowing them to establish while the soil is still relatively warm and damp.

Not just ornamental, they’re of practical value too. Burnt for charcoal, the hard, dense wood has also been used to make arrows, herding and walking sticks, small tools and, somewhat obscurely, butchers’ skewers. Also known as ‘dags’ or ‘dogs’, it’s thought these may be the origin of the plant’s common name, dogwood, although other sources have it that the wood gave its name to the skewers. Cornus bark is rich in tannins and has been used in traditional medicine.

Autumn and winter interest:

Leaves, stems and berries

Cornus’ oval leaves with their distinct, curving veins are an asset in summer but it’s in autumn that they really come into their own with dramatic displays in fiery hues from gold, tangerine and bronze through scarlet, crimson and plum. There are berries too – purplish black, white or red, some contrasting with the flaming leaves and stems.

 Those grown for their stem colour have the greatest impact when planted in groups. They’re often seen in winter gardens like the one at Anglesey Abbey in Cambridgeshire, set against a ghostly backdrop of white-barked silver birch and dotted with early spring bulbs. If planting individually in small spaces, place them in front of evergreen shrubs whose leaves will provide the perfect backdrop.

These types prefer moist but not boggy soil that doesn’t dry out. Annual hard pruning as well as full sun encourages the best colour. Leave plants for the first year after planting, then chop back in spring – March is best – to around 6cm or 2-3 inches from the ground. Bear in mind, though, that when coppiced in this way they’re less likely to produce flowers or berries the following season.

https://www.rhs.org.uk/garden-inspiration/gardens-we-love/inspirational-winter-gardens-to-visit

Cornus for stem colour:

1. sanguinea ‘Midwinter Fire’ is yellow at the base, deepening up the stems to orange and then scarlet. Berries are black.

The stems of C. alba ‘Sibirica’ are red, taking on purple hues in winter. White berries create a stark contrast to the wine red and purplish autumn leaves.

1. alba ‘Kesselringii’ has dark, almost black stems, dark reddish purple autumn leaves and white berries.

1. sericea ‘Flaviramea’ has golden yellow to lime stems with white berries and leaves that turn a deep orange red in autumn.

All have small, creamy white flowers in early summer too and grow to about 2 x 2m.

https://www.rhs.org.uk/plants/cornus/for-stems/growing-guide

Flowers

A boon for early bees, clusters of tiny, glowing yellow flowers appear on the bare stems of Cornus mas in late winter and on through early spring. These are followed by red berries in late summer with leaves turning purplish in autumn before falling. Plant in full sun in a sheltered spot in neutral to acid soil. Approximate height and spread 4 x 4m.

Spring interest:

Leaves

As the days become longer and begin to warm, new foliage appears, its freshness of colour often offset by coloured stems.  Cornus alba ‘Kesselringii’ has pale green leaves with bronzy tints while the emerging leaves of ‘Sibirica’ and C. sanguinea are lime green.

Summer interest:

Flowers

Flowering dogwoods don’t, as a rule, need pruning, except to remove dead or diseased branches. Many are slow growing and the architectural beauty of C. controversa would be spoiled if interfered with by loppers, although as trees become mature, removing one or two lower branches to create a clear trunk may enhance their appearance. Most have good autumn colour with leaves that curve gently downwards, adding to their grace. They prefer moist but well-drained, neutral to acid soils.

The most magnificent of dogwoods, C. controversa, the wedding cake tree, has branches in well-defined tiers which display white, star-like flowers along their length in midsummer. These are held in flat upright clusters, emerging lime green and maturing to white. The leaves turn gold or red as the season changes and autumn berries ripen from green to gold to black. It can grow into a fairly substantial tree – up to 15 x 15m. ‘Variegata’, however, is more manageable at 8-10m, its leaves creamy white around the edges.

The spectacular show put on in early summer by other cornus grown for their blooms actually comes from bracts or modified leaves which have the appearance of flowers. Most are white but there are pink varieties too. The flower itself is the often rounded, greenish, cone-like centre of the four ‘petals’.

The bracts of C. kousa var chinensis mature from greenish to creamy white, aging to shades of pink. These are followed, on mature trees, by deep pink fruits with an intriguing similarity to strawberries. Leaves turn gold, bronze and reddish pink in autumn.

1. kousa ‘Miss Satomi’ has deep pink bracts with dark green foliage turning purplish red in autumn and fruits similar to those of C. kousa var chinensis.

1. C. ‘Eddie’s White Wonder’ has large white bracts with golden, purple and red leaves in autumn.

All three, as well as other C. kousa cultivars and C. florida, grow to around 6 x 6m tall

Their size, habit and features make them a valuable addition to smaller as well as large gardens as splendid specimen plants in lawns or adding interest to the edges of woodland plantings.

And a mention too for ground-hugging C. canadensis, a small, spreading shrub with white bracts in early summer surrounding clusters of tiny, starburst flowers. Preferring part shade, it grows to around 15cm x 1m, with clusters of red berries in autumn. One of its more unusual characteristics is its ability to fire pollen into the air at tremendous speeds as the flowers open. So fast, in fact, that the pollen is said to experience a gravitational force 800 times that of an astronaut taking off in the space shuttle.

https://www.sciencenews.org/article/worlds-fastest-plant-explodes-pollen

We may not have all the plants listed in our stores but our staff will be happy to suggest alternatives.

https://www.gardenersworld.com/how-to/grow-plants/how-to-grow-cornus/

A joy to behold and with botanical riches on offer throughout the year, cornus are an asset to gardens large and small. Hard-working, reliable and excellent value for money, they have it all.