<em>Griselinia</em>, Griseline: planting, pruning and care

Botany and description

Griselinias originate from temperate regions of the southern hemisphere, mainly Chile and New Zealand. The genus comprises about ten species but you will scarcely find in our area anything other than Griselinia littoralis or Coastal Griselinia, and sometimes Griselina lucida, both native to New Zealand. Its other common names are: New Zealand Griselinia or English Spindle. Formerly placed in the Cornaceae family, Griselinias are now classified in their own family: Griseliniaceae (since APG II). For curious gardeners or collectors, here are the other Griselinia species: G. carlomunozii, G. jodinifolia, G. racemosa, G. ruscifolia, G. scandens and G. alata.

It is a bush or small tree capable of reaching 10 metres in its natural habitat but rarely exceeding 3 metres in our climate. Habit is bushy, compact and well ramified. Bark is smooth and greyish but fissures with age. Growth rate depends on cultivar but remains around 50 cm per year for Griselinia littoralis. Griselina lucida develops more vigorously, up to 5 m in our regions, and foliage is slightly darker.

Griselinia’s foliage is alternate and evergreen: leaves thicken and become leathery with age. The leaves are glossy and apple-green, veins and petiole remaining paler (almost yellow) than the lamina. Leaf underside is also paler and more matte. Each leaf measures between 4 and 12 cm and is ovate and incurved. Note that cultivars exist with foliage variegated in white or yellow, as well as cultivars with a more emerald green foliage.

The bush is dioecious, meaning there are male and female plants. Flowering is inconspicuous to our eyes but attracts and feeds many pollinating insects. Flowers appear between May and June and are arranged in axillary panicles of hundreds of tiny greenish flowers (a few millimetres), apetalous, with five stamens and three styles, and protected by a calyx of five sepals (on female plants).

Griselinia littoralis with striking apple-green foliage and Griselinia littoralis ‘Bantry Bay’ with superb cream-variegated foliage

After fertilization and only on female plants, fruiting follows as small clusters of berries first green then black at ripeness, each containing a single seed.

Main varieties

New Zealand broadleaf - Griselinia littoralis

Type species originates from New Zealand. Bush has a bushy habit and very dense, evergreen foliage of an astonishing apple-green. Performs splendidly as a windbreak in coastal gardens. Note that flowering, although discreet, delights pollinating insects.

• Flowering time June, July
• Height at maturity 2,50 m

See the product sheet

Griselinia littoralis Redge

This variety is distinguished by lower height and vigour compared with type species (growth of only 30 cm per year...). However, its abundant branching and attractive glossy foliage, which contrasts strongly with almost black branches, make it a good choice for a lower hedge.

• Flowering time June, July
• Height at maturity 1,80 m

See the product sheet

Planting Griselinia

Where to plant your Griselinia?

Although moderately hardy, Griselinia thrive mainly in the south of France and along the coastline thanks to their resistance to sea spray. This is unsurprising, as in their country of origin they grow along coasts.

This attractive bush adapts to different soils but prefers sandy ground. Neutral soil suits it perfectly and most varieties tolerate calcareous conditions very well (‘Pointe du Raz’, however, prefers slightly acidic soil). And of course, plant your Griselinia in well-drained soil: it would not tolerate having its roots “in water” in winter; that would be fatal.

It is customary to place it in full sun to obtain good flowering and to accentuate the glossy foliage. But it can perfectly well be planted in partial shade. It will grow very well there but will flower a little less.

It is particularly resistant to wind and sea spray, making it an excellent choice for hedges in seaside gardens.

When to plant?

As with all bushes with evergreen foliage, Griselinia is best planted in early autumn, from September to October. If you missed that window, no problem: planting between April and June is also fine. Also, because the bush is grown in a container, you can in theory plant it at any time outside heatwaves or frosts — but remember to monitor watering!

How to plant?

• Start by soaking your Griselinia pot for a few minutes in a bucket of lukewarm water
• Dig a hole two to three times the volume of the rootball
• If your soil is neither sandy nor particularly well drained, mix the excavated soil with some gravel and a little potting compost. This will improve drainage.
• At the bottom of the hole, you can add a few handfuls of well-rotted manure or well-matured compost to give roots a good start
• Remove the plant from its pot and gently break up the rootball to free the roots
• Place the bush in the centre of the hole and begin backfilling with your soil + gravel + potting compost mixture
• Keep the plant’s collar out of the soil and firm the soil with your fingers
• Water well at the base to reduce any “air pocket” between roots and soil
• Mulching is appreciated, especially during the first years.

Griselinia hedge

Care and maintenance

Care

In open ground, do not hesitate to water during the year following planting if the season is dry. Mulch at the base helps keep the soil cool for longer.

Growing in a container is a little more delicate: make sure never to let the potting mix dry out and, above all, remember to protect your bush with a winter fleece if temperature falls below -5°C and if it is exposed to wind. Indeed, the bush is more sensitive in a container than in open ground.

Pruning

Prune only after flowering, insects will thank you! So, in practice, prune only in July or September. If you do not want to prune too often (or at all!), you can opt for varieties with reduced growth.

Pruning is simple: shorten stems that seem to be escaping from the bush to keep branches compact. If, on the other hand, you favour slightly free and wild hedges, do not touch anything!

Possible diseases and pests

No pest will attack your Griselinia. However, soil moisture, especially in winter, will be fatal. It can also cause fungal diseases: foliage becomes covered with blackish or orangey spots and eventually falls. The bush’s vigour is greatly reduced. If this happens to you, there are few solutions: either move it to a more suitable spot, or improve drainage there by mixing the surrounding soil with sand and gravel.

Propagation: propagating Griselinia

When?

At late-summer pruning: late August–early September, take shoots of about 20 centimetres from semi-ripe terminal stems (not yet lignified).

How to propagate Griselinia?

• Remove all leaves except the 2 terminal leaves. This is necessary for all cuttings in general, as it limits water loss by evaporation.
• Re-cut the base of the shoots on the slant just below a bud (or eye) with a clean, disinfected cutting tool (flamed or wiped with 90% alcohol). Re-cutting like this increases the contact surface between stem and substrate.
• Prepare a very light growing medium: 1/3 multipurpose compost and 2/3 sand.
• Fill pots or, better still, the tray of a mini greenhouse (with a tall dome if possible).
• Dip the end of your cuttings into rooting plant hormone if available. A few willow stems soaked for a few hours in water can replace rooting hormone: either dip cuttings into that water or water with it.
• Push your cuttings into the growing medium up to the lowest remaining leaves.
• Moisten the compost then cover with a plastic bag, half a plastic bottle or the dome of your mini greenhouse to keep cuttings in a warm, humid environment. Tip: cuttings root better and more quickly when placed near edge of pot or tray.
• Place cuttings in partial shade (but still bright) and definitely not in sun!! In a few minutes cuttings would be scorched (true!).
• Do not touch anything for a week. You can check occasionally but best to keep everything closed (you can see through dome or plastic bag anyway).
• Sometimes cuttings lose their leaves. No need to worry as long as shoots are not black, all is well.
• Shelter cuttings from frost over winter then transplant out to garden from following April.

→ Learn more in our tutorial : How to propagate Griselinia?

Companion planting in the garden

Within an informal hedge in a seaside garden

Griselinia littoralis is perfectly at home in an informal hedge of a coastal garden. To accompany it, charming hybrid Grevillea juniperina ‘Canberra Gem’ with a bushy habit and an endless pink-red flowering. Erythrina x bidwillii, with its strange name, is a spectacular bush producing huge clusters of bright red flowers and can complete the hedge, as can a “single” Callistemon citrinus ‘Burgundy’, a bottlebrush with deep burgundy brushes. Add a handsome Escallonia laevis ‘Gold Ellen’ with golden evergreen foliage and vivid pink flowering and, why not, a small Ceanothus pallidus ‘Marie Simon’ whose gentle flowering will temper the vigour of the brighter-flowering bushes mentioned earlier. This attractive hedge will be in flower for much of the year. It will also withstand sea spray and wind while sheltering you within your garden. Note that most of the bushes listed have evergreen foliage that will brighten the garden all year round.

An example of an association in a seaside hedge: Griselinia littoralis, Grevillea juniperina ‘Canberra Gem’, Erythrina x bidwillii, Callistemon laevis (or C. citrinus ‘Burgundy’), Escallonia laevis ‘Gold Ellen’

In a pot on a terrace

Griselinia littoralis ‘Redge’ is a more compact variety than the type species and therefore particularly suited to pot culture. Less than two metres tall and about one metre wide, its vigour can be tempered with a few well-placed pruning shear cuts. But rest assured, it grows more slowly than the type species: about 30 cm per year. To accompany it, the remarkable Melaleuca gibbosa, or Niaouli, with extremely long mauve flowering, sometimes all year if the climate is mild enough. It is a bush that thrives in a pot and is very drought-tolerant. Eucalyptus gunnii ‘France Bleue Rengun’ is a French novelty. This Eucalyptus, with very fine bluish and gently aromatic foliage carried on a very architectural columnar silhouette, is a true plant jewel on your terrace. Despite reaching around two metres, this small tree grows very well in a large pot. A few Agapanthus ‘Blue Storm’ with blue flowering will complete the picture, as will a handsome Agave americana whose bluish tones will echo the foliage of the Eucalyptus. Grasses are unrivalled at lightening a composition thanks to their spikes dancing in the breeze. A few clumps of Pennisetum setaceum ‘Ruppellianum’ will be wonderful in this role alongside your Girselinia.

An example of a pot combination: Melaleuca gibbosa, Eucalyptus gunnii ‘France Bleu Rengun’, Griselinia littoralis ‘Redge’, Agapanthus ‘Blue Storm’, Pennisetum setaceum ‘Ruppellianum’ and Agave americana

Did you know?

• Griselinia is native to New Zealand. Like many plants imported from that country, it naturalised rapidly near seashores, notably on the Atlantic midrib.
• Its name honours 18th-century Italian naturalist Francesco Griselini