<em>Griselinia</em>, Griseline: plant, prune and care for

Botany and description

Griselinias originate from temperate regions of the Southern Hemisphere, mainly Chile and New Zealand. The genus includes around ten species but you will find almost exclusively Griselinia littoralis or coastal Griselinia here, and sometimes Griselina lucida, both native to New Zealand. Other common names are: New Zealand Griselinia or English spindle. Formerly placed in family Cornaceae, 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 here. Habit is bushy, compact and well ramified. Bark is smooth and greyish but becomes fissured with age. Growth rate depends on variety 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 foliage is alternate and evergreen: leaves thicken and become coriaceous with time. The leaves are glossy and a striking “apple-green” colour, veins and petiole remaining paler (almost yellow) than the lamina. Leaf underside is also paler and more matt. Each leaf measures between 4 and 12 cm and is ovate and incurved. Note that there are cultivars with foliage variegated in white or yellow, as well as cultivars with a more emerald-green foliage.

The bush is dioecious, which means there are male and female plants. Flowering is insignificant 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 5 stamens and 3 styles and protected by a calyx of 5 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 specimens, fructification follows in small clusters of berries first green then black at ripeness containing a single seed each.

Main varieties

New Zealand broadleaf - Griselinia littoralis

This is the type species native to New Zealand. The bush displays a bushy habit and very dense evergreen foliage of a striking apple-green. It makes an excellent windbreak screen in coastal gardens. Note that its flowering, though discreet, delights pollinators.

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

See the product sheet

Griselinia littoralis Redge

This variety is characterised by lower height and vigour compared with the type species (growth of only 30 cm per year...). However, its abundant branching and attractive glossy foliage, strongly contrasting with the 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 only moderately hardy, Griselinia do particularly well in south of France and along coastlines thanks to their resistance to sea spray. This is unsurprising as in their native range they grow along coasts.

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

Usually placed in full sun to obtain good flowering and enhance glossy foliage. But, it can perfectly be planted in partial shade. It will grow very well there but produce slightly fewer flowers.

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

When to plant?

As with all evergreen shrubs, Griselinia is best planted in early autumn, from September to October. If you miss that window, no problem: planting between April and June is also fine. Moreover, as 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‘s 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 excavated soil with some gravel and a little potting compost. This will improve drainage.
• At bottom of hole, add a few handfuls of well-rotted manure or well-matured compost to give roots a good start
• Take plant out of pot and gently “break up” the rootball to free roots
• Place the bush in centre of hole and begin backfilling with your soil + gravel + potting compost mix
• Keep plant’s collar above soil and firm it with your fingers
• Give a thorough watering at the base to reduce “air pockets” between roots and soil
• Mulch is recommended, especially in early years.

Griselinia hedge

Care and maintenance

Care

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

Growing in a container is a little more delicate: ensure the potting mix never dries out and, above all, protect your bush with a winter fleece if the temperature falls below -5°C and it is exposed to winds. Indeed, the bush is more sensitive in a container than in the 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 often (or at all!), you can choose varieties with reduced growth.

Pruning is simple: just shorten shoots that seem to be escaping from the bush to maintain compact branches. If, on the other hand, you favour slightly free, wild hedges, leave everything alone!

Possible diseases and pests

No pests will attack your Griselinia. However, soil moisture, especially in winter, can be fatal. It can also lead to fungal diseases: foliage becomes covered with blackish or orange spots and eventually falls. The bush’s vigour is greatly reduced. If that happens to you, there are only a couple of solutions: either move it to a spot that suits it better, or improve drainage there by mixing the surrounding soil with sand and gravel.

Propagation: propagate Griselinia

When?

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

How to propagate Griselinia?

• Remove all leaves except two terminal leaves. This operation is necessary for cuttings in general, as it limits water loss by evaporation.
• Cut the shoots on a slant at the base just below a bud (or eye) with a clean, disinfected cutting tool (by flame or 90% alcohol). Cutting like this provides a larger contact surface between stem and substrate.
• Prepare a very light substrate: 1/3 universal potting compost and 2/3 sand.
• Fill pots or, better still, the tray of a mini-greenhouse (with a high dome if possible).
• Dip ends of cuttings in plant hormone for propagation by cuttings if available. A few willow discs soaked for a few hours in water can replace the plant hormone: simply dip cuttings in the liquid or water with it.
• Push cuttings into substrate up to last leaves.
• Moisten compost then cover with a plastic bag, half a water bottle or the dome of your mini-greenhouse to keep cuttings “in a steamy atmosphere” (warm, humid conditions). Tip: cuttings root better and faster when placed near edge of pot or tray.
• Place cuttings in partial shade (but still bright) and certainly not in direct sun!! In a few minutes cuttings would be scorched (true!).
• Don’t touch anything for a week. You can occasionally check all is well but best to keep everything closed (anyway, you can see through dome or plastic bag).
• Sometimes cuttings lose their leaves. No need to worry as long as shoots are not black, all is well.
• Protect cuttings from frost in winter then transplant outdoors from April of the following year.

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

Companion planting

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, this charming hybrid Grevillea juniperina ‘Canberra Gem’ with a bushy habit and an endless pink-red flowering. Erythrina X Bidwillii, with its curious name, is a spectacular bush with huge clusters of vivid red flowers that can complete the hedge, as can a “single” Callistemon citrinus ‘Burgundy’, a bottlebrush with deep burgundy brushes. Add also a handsome Escallonia laevis ‘Gold Ellen’ with golden evergreen foliage and bright pink flowering and, why not, a small Ceanothus pallidus ‘Marie Simon’ whose gentle flowering will temper the more vivid displays of the preceding bushes. This delightful 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 mentioned have evergreen foliage that will brighten the garden all year round.

An example planting combination 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 species and therefore particularly suited to container growing. Under two metres tall for about one metre wide, its vigour can be restrained with a few well-placed cuts from pruning shears. Rest assured, it grows more slowly than the species: about 30 cm per year. To accompany it, this striking Melaleuca gibbosa, or niaouli, with an extremely long mauve flowering, sometimes year-round if climate is mild enough. It is a bush that thrives in a pot and tolerates drought very well. Eucalyptus gunnii ‘France Bleue Rengun’ is a recent French introduction. This Eucalyptus, with very fine bluish, gently aromatic foliage carried on a very architectural columnar silhouette, is a true plant gem for your terrace. Despite a eventual height of two metres, this small tree does very well in a large pot. A few Agapanthus ‘Blue Storm’ with blue flowering will complete the picture, along with a fine Agave americana whose bluish tones will echo the Eucalyptus foliage. Grasses are unrivalled at lightening a composition thanks to their spikes dancing in the breeze. A few clumps of Pennisetum setaceum ‘Rupellianum’ will work wonders in this role beside your Griselinia.

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

Did you know?

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