How to grow flowering dogwood

Choosing a flowering dogwood

This versatile group of dogwoods (Cornus) can be grown as a feature trees or a large shrub. There’s also one herbaceous

Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

Once you’ve decided what size of plant you’d like, the next choice is the flower size and shade of white or pink. It’s worth noting that most flowering cornus produce immature green flowers, which then change to their mature colour (so the one as advertised on the label), before typically turning pink later in summer. So just be aware that if you want pure white, you will still get pink tinges as the flower bracts age.

C. mas and C. officiinalis are tougher winter flowering types that usually establish more easily and bring cheerful yellow blooms to announce that spring is nearly here.

Cornus are a investment – in time as well as money –  so it is important to consider their eventual size and give them the growing conditions right. However, with show-stopping flowers and a graceful habits, they are worth the extra effort.

Buying a flowering dogwood

Some flowering cornus are available in garden centres, but you will probably get a bigger choice from specialist nurseries and mail order suppliers.

They are available in pots with sizes ranging from small younger saplings to large mature specimens.

Before deciding, you might like to see the trees and shrubs you’re interested growing in a garden. The National Collection of Cornus can be found at Newby Hall, North Yorkshire. There’s also a great selection to see at RHS Garden Wisley in Surrey in early summer.

Flowering dogwood can be planted from autumn to early spring. As their delicate papery leaves are prone to scorch and browning around the edges due to not quite enough water at the roots, summer planting is best avoided.

• Make the most of these trees and shrubs by planting them in the sun or dappled shade
• Flowering cornus really thrive on moist but well-drained soil. Cornus kousa (from Korea and Japan) prefers neutral to acidic soil; whereas north American species, such as C. florida and C. nuttallii, are more tolerant of neutral to alkaline soils. While it’s hard to change soil pH, you can improve moisture retention by improve it before planting by digging in a bucketful of well-rotted garden compost, leaf-mould or manure per sq m
• As slow-growing trees, they can take their time to establish and will often need watering in dry spells for at least three to four years after planting. But, once they have made themselves at home, they will prove it’s been worth the extra care
• Trees that are more than 2-3ft (60-90cm) when you by them really require staking to prevent the tree from rocking or developing a lean

RHS guide to planting trees and shrubs

RHS guide to planting trees and shrubs

Watering

• Flowering dogwood do take their time to establish, so will require watering regularly up to four years.  After establishment, they will only need watering during long dry spells (drought)
• Do check the soil is actually dry before you water, as the papery leaves of flowering cornus are very good a wilting just to cope with the heat and will perk up again once the sun is lower in the evening

Feeding

• On poor soils where you need to promote growth, apply a balance feed in late winter, such as Growmore or blood fish and bone
• Improve the soil by mulching with well-rotted organic matter or composted bark. Just leave a gap between the mulch and the trunk, so that it doesn’t touch and cause rot

Caring for older plants

• After their troublesome establishment phase is through, flowering dogwoods are the perfect garden additions and will provide interest the whole year through for many years. Little care is needed and pruning is positively discouraged

Flowering dogwoods do not require regular pruning. Indeed, other than enhancing the shape, it’s best to put away your pruning tools – particularly as the tree matures.

While they are young, trimming them here and there to get that perfect silhouette with beautifully placed branches is best option.

Prune when dormant from late autumn to early spring. Create a clear trunk on young trees by removing branches as the tree grows. The smaller the branch the smaller the scar left to heal.

Flowering dogwoods do not respond well to heavy pruning and to do so could spoil their habit and shape. 

Cornus controversa has a natural tiered habit where the branches are held out at right angles descending up in rows. Give the plant plenty of space to begin with so it naturally grows into the best shape, as cutting it to fit will spoil the overall look. However, sometimes you will get an upright stem that could potentially merge two tiers together, so this can be cut off cleanly with secatuers.

Softwood cuttings: In late spring or early summer, take softwood cuttings. The soft leaves of flowering dogwoods can dry out very quickly so it is important to take the cutting in the morning when the wood is firm.

Then, to take the cutting, select healthy young soft shoot tips and cut them off the parent plant. Prepare this further by cutting under a pair of leaves at the base, leaving a cutting about 5-10cm (2-4 in) in length. The exact length just depends on how spaced out the leaves are on the shoot.

Put the prepared cuttings into pots of cuttings compost (half multi-purpose and half horticultural grit or perlite) as soon as you can to prevent drying out and improve the success rate.

RHS guide to softwood cuttings

RHS guide to softwood cuttings

Generally flowering cornus are grafted as this speeds up the process – so get you get a flowering tree a few years quicker.

The lower part of the tree is usually a seed raised rootstock. Then the top, which is call the scion, is selected from the desired cultivar will be prepared so the cut surfaces of rootstock and scion match up and will grow together. It’s a technique that requires a bit of practice, so you might need to give it several goes to get success.

Grafting ornamental plants and fruit trees

Grafting ornamental plants and fruit trees

Seeds: Collect fresh ripe red fruit in autumn and then soak them for several days in warm water to remove the fruit pulp from around the inner seed. Once the seed is clean by washing in a sieve, store it in a bag of slightly damp sand in the fridge as they need a cold spell before germination. Sow the seed in late winter-early spring and keep them at a temperature of 15-21°C to encourage germination.

Growing trees from seed

Growing trees from seed

In wet springs, watch out for possible infections of Cornus anthracnose. Flowering dogwoods can also be susceptible to root diseases, such as honey fungus and Phytophora root rot.