Philadelphus

When you first experience the heady scent of philadelphus you could be forgiven for thinking you’ve gone to heaven. The only mystery is why this wonderful shrub isn’t more popular, because it deserves to be. This super shrub really does deserve wider recognition as one of the most versatile spring flowering plants for our gardens, especially if you’re in an area with cool winters.

Plant details

Common name: Mock orange

Botanic name: Philadelphus

Climate: In the wild they originate in countries with warm summers and cold winters, growing on the slopes of mountains ranging across the world from western China to Mexico and southern and western USA, through to Italy and Austria. However, they have proved to be very adaptable in a variety of temperate climatic zones. They will grow in all areas of Australia except the tropics, from around Brisbane and south.

Description: Philadelphus species do vary in size, but many are medium shrubs growing to a height and spread around 3m (10′). Many, but not all, varieties are deciduous and bear white flowers in late spring and early summer, with that fabulous, orange-like scent.

Best varieties: Philadelphus ‘Virginal’ is possibly the best known in Australia and for this treasure we have to thank Monsieur Victor Lemoine, a French nurseryman who began in 1883 to hybridise the genus as the different species became available, and continued releasing new cultivars until 1920.

Crossing a European species, P. coronarius, with the American P. microphyllus, he produced P. ‘Lemoinei’ in 1884. Following this his nursery introduced a series of new varieties: ‘Avalanche’ in 1896, ‘Conquette’ in 1903, ‘Virginal’ and ‘Norma’ in 1909, and all were beautiful, fresh pure white.

Using P. ‘Lemoinei’ and P. maculatus, he then created a new group of hybrids beginning with ‘Sybille’ in 1909, which has a maroon pink flush to the centre of each flower. Later came ‘Bicolore’ in 1918, with a stronger flush of colour, but this one does not appear to have been imported into Australia.

Later introductions such as ‘Belle Etoile’ and ‘Etoile Rose’ both flush soft pink, and they are sometimes offered in nurseries. More lovely hybrids have arisen including ‘Minnesota Snowflake’, ‘Albatre’, ‘Manteau d’Hermine’ and ‘Frosty Morn’.

‘Albatre’, like ‘Virginal’, has flowers which are cupped with petaloids in the centre. The greater the number of petaloids the more double the flower is said to be. ‘Albatre’ grows to around 1.5m (5′), and ‘Frosty Morn’, which has small leaves and an upright habit, is a charmer with a double row of pointed petals in a perfect rosette. ‘Minnesota Snowflake’, as the name implies, has a multitude of pointed petaloids filling the centre of each flower which, when spent, carpet the ground very prettily. If you’d prefer a smaller variety, ‘Manteau d’Hermine’, at 1m (3′) is ideal for small gardens. Its flowers are semi-double and it will repeat flower in autumn.

The cultivar P. coronarius ‘Aureus’, with its butter yellow spring foliage and white blossom, is a delight when planted in a woodland garden. The foliage ultimately changes to green as summer begins.

For warmer areas such as Brisbane, Philadelphus mexicanus is probably the best choice. It can reach up to 6m (20′), but with a spread just under 2m (6′). In mild climates it is the only species which remains evergreen. It has cream, cupped and highly perfumed flowers.

Best look: Gardeners visiting spring gardens in New Zealand or England cannot fail to notice how these beautiful shrubs, often with arching to slightly pendulous growth habits, are covered with snow-white, deliciously scented flowers. They are especially effective when used in borders or as background to old-fashioned roses.

Care:

will grow in full sun but will also flower prolifically in dappled or half-day shade
Philadelphus are not fussy as to soil type
protect from strong wind
normal watering, fertilising and mulching to give best results
prune after flowering by removing some of the oldest basal canes so new canes can develop. Shorten the remaining canes to encourage stronger laterals which give rise to next spring’s display.

Availability

Philadelphus are available from specialist nurseries around the country.

NSW: Colonial Cottage Nursery, Dural, phone: (02) 9654 1340.

SA: Vadoulis Garden Centre, Gawler, phone: (08) 8522 3400

Tasmania: Woodbank Nursery, Longley, phone: (03) 6239 6452.

Victoria: Digger’s Seeds, Dromana, phone: (03) 5987 1877.

Costs: A rough price guide only, small pots, 14cm (6″), are from $6-$8, and larger 20cm pots are from $15-$18.

Further reading

For more information on philadelphus see the article in the October 1998 issue of the Burke’s Backyard magazine on page 44.

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