Pieris, is known as Pearl Flower or Lily of the Valley Bush, also Andromeda. This is a small genus of 7 or 8 shrubby species with a big reputation. They are known to be highly ornamental in all seasons, compact, evergreen, nearly maintenance free.
And very hardy in a wide variety of garden and courtyard situations. Pieris are related to both Azaleas and Kalmia (Mountain Laurel). They are members of the large Ericaceae (Heath) Family. These are woodland plants mostly native to higher elevations in temperate mountain climates of Japan, East and South Asia (China and Taiwan), Eastern Siberia, the Himalayan Mountains and one species comes from the mountains of the South Eastern United States and highland Cuba.
Lily of the Valley Bush gets this common name because the flowers so closely resemble large clusters of Convallaria (Lily-of-the-Valley). Some flower cultivars carry a soft honey-musk perfume but it is their lovely flower form that is so dramatic. Flowers are small, pearl-like waxy clusters of gracefully nodding bell-shaped flowers carried in small chains.
These flower chains are produced in impressive clusters at the ends of the branches. Flower buds become noticeable later in the Autumn and open from Late Winter through Spring. They are long-flowering and quite weather resistant blooms that often nearly cover the entire shrub in cream, pastel pink and pearly white bells.
Decorative evergreen foliage is quite a bonus as Pieris will thrive from Zone 5-9+ and even in quite subtropical conditions in light shade. They are tolerant of considerable Winter cold provided their dormant exposed flower buds are not subjected to severe drying winds which also increase destructive wind chill.
If this were to occur, the foliage would be burnt and flower clusters ruined. But if such cold were not a regular Winter occurrence, the shrubs would bounce back quickly with new growth in Spring. And would usually produce another set of flower buds late the following Autumn ready for Spring flowering.
Pieris is quite a durable broad-leafed evergreen featuring lanceolate-ovate simple leaves which can be narrow or broad and somewhat leathery. Leaves tend to spiral up the branching stems and appear as clustered whorls at the ends of the branches. Mature older foliage tends to drop and self-mulch beneath the shrub. This creates a somewhat open interior structure of branches with a leafy overhead canopy.
Early Spring new foliage on most Pieris species first emerges an attractive lighter green before turning deeper green once mature in the Summer. But in many modern cultivars, especially of Pieris japonica, the new foliage is sometimes bronze, copper to purple and highly decorative. Some start as leafy plumes of orange or even scarlet then gradually change to cream or cream/green before turning deep, rich green in summer. Some stay fiery red then turn deep green. Some look almost like artificial plastic foliage with a translucent waxy quality that is quite attractive and distinctive.
Hybrid cultivar Pieris ‘Forest Flame’ is a hybrid cross between a bronze foliaged Pieris japonica and brick red foliaged Himalayan Pieris formosa. This created a series of spectacular cultivars of which Forest Flame is best known. The Forest Flame cultivar features nearly scarlet red new foliage that sets this shrub apart from all other Pieris. Forest Flame really lives up to its name each Spring when the entire shrub turns crimson to scarlet red. Many of these ‘flame’ cultivars also feature porcelain pink to nearly scarlet red flower clusters. Others feature deep red stems with white bell-shaped flowers. These are most handsome and ornamental shrubs for something really ‘special’ in the shrub garden.
Similar hybrid cultivars include:
Pieris ‘Red Mill’ has bright brick red to orange red new foliage which is brightest in stronger (but ‘soft’ morning) sunlight. In light shade the new foliage is bright bronze/copper/orange.
Pieris ‘Flaming Silver’ is a dwarf variegated form featuring very deep forest green leaves streaked in silvery white. New foliage is vivid waxy pinkish/red.
Pieris japonica ‘Mountain Fire’ features similar shaped dark green foliage when fully mature over vivid blazing red new Spring growth.
Pieris japonica variegata is the standard variegated form of Pieris with more olive-green foliage and a creamy variegation with bronze-copper new foliage. This cultivar usually has cream or white flowers, some cultivars feature a blush of pink in the blooms.
Pieris japonica ‘Little Heath’ is a pretty dense and smaller cultivar with deep forest green foliage and well-formed pearly white flower clusters. It is very decorative.
Pieris japonica ‘Carnaval’ is a beautiful dwarf species, ideal for pots; featuring thin, delicate variegated mature foliage topped with bright clusters of crimson red new growth creating a stunning impression for the partly shaded garden.
Pieris japonica ‘Valley Rose’ features long thin chains of small pink and white pearly flowers on a hardy robust shrub.
Pieris japonica ‘Valley Valentine’ has most impressive chains of larger bright to deep pink flowers. In some of the most recent hybrid cultivars from ‘Valentine’ the shrubs produce waxy large flowers closely resembling bright candy red hearts on a pendulous red-stemmed chain. Very decorative!
Pieris japonica ‘Cavantine’, ‘Purity’, ‘Sarabande’, ‘White Cascade’ and many more exquisite cultivars feature various forms of pure pearly white flower forms
The Australian hybrid Pieris japonica ‘Bert Chandler’ has exotic salmon pink foliage which changes to cream then white and eventually bright green. This is an unusually striking hybrid cultivar that is so brilliant that it often deserves a spot on its own. Or it also looks very nice when planted with the rich green foliage of Azalea and Kalmia (Mountain Laurel), especially pink and white flowering forms. The pink and white new foliage of Bert Chandler adds a beautiful complement as this foliage is at its best brilliance about the time that the Azaleas and Mountain Laurels also come into bloom.
Pieris floribunda, the Mountain Fetterbush , Mountain Andromeda or Andromeda floribunda is a rather uncommon native of the South Eastern United States usually found in the Appalachian Mountains from Virginia to Georgia and especially in the lovely misty mountains of Western North Carolina. The 1-1.2/3-4ft shrub closely resembles the growing habit of a Daphne with glossy simple evergreen leaves that resemble both Daphne and Kalmia latifolia (Mountain Laurel) which is a close relative. Some varieties feature slightly larger foliage a bit reminiscent of Sweet Bay Laurel or Sasanqua Camellia. The delicate white bell-shaped flowers are pendulous but held on upright stems at the ends of the branches and appear in Spring. The leaves of Mountain Fetterbush have been used to treat headache, muscle and back pain. They are well-crushed and made into a poultice or their juice is added to the compress or dressing. Caution! Mountain Fetterbush leaves are highly poisonous and not to ever be eaten!!!
Pieris formosa forrestil from Burma is a vigorous grower to 4+m/13-15ft. This species is often known as ‘Andromeda’. Large panicle clusters of creamy flowers cover the shrub in pearly chains from Late Winter through Spring. New foliage is bronze-copper green. The green seed pods that follow are also decorative. The whorls of seed stems fan out like little umbrella spokes lined with small pendulous pea seeds attached down their length. These can be dried if picked before they fully ripen.
Andromeda is a really impressive large shrub or small tree which prefers a little more shelter than the rest to gain its full height. But is so durable that it sometimes performs well even in nearly full sunshine provided the soil is ideal, constantly moist and the climate remains suitably cool and humid during the Summer months. These are often seen as lawn specimens right out in the open.
Most other Pieris species will also accommodate a lot more sunshine than one would expect from their native origins provided they have ideal growing conditions. These are quite durable, hardy and long-lived shrubs when placed in the right position.
The secret with Pieris is to closely recreate their higher elevation mountain conditions. Thus they prefer very freely draining, sometimes almost sandy soil but with plenty of water-retentive humus and organic content. They thrive in loamy soils and pasture land as well, provided the soil is both somewhat water-retentive but also freely draining.
This soil should also be of a slightly acid soil pH 5.5-7.0. They do best in the average garden when planted in a mildly acid soil rich in leaf mould with plenty of sand and peat mixed in for good drainage. They like damp locations with high humidity to keep the foliage lush and glossy green. But they are highly intolerant of poorly draining, heavy wet soils or any soils with a high Lime content.
Avoid ‘wet feet’ with this shrub. Cold weather with prolonged wet soil will often first reveal itself as blackened foliage tips or entire soon-blackened leaves. Which soon turn dry and crispy. The uninitiated novice Gardener is often fooled at this point thinking that the shrub is getting to ‘dry’ and then adding more water only to see entire stems turn black and die! The secret is to increase cultivation; possibly sprinkle Gypsum beneath the shrub and no more watering for a while!
Because of their mountainous heritage and need for continual humidity and moisture, provide Pieris with generous mulch. This should be at least 2-4in/5-10cm deep at all times, especially during the drier and warm Summer months. Year-round organic mulch is an ideal way to avoid the need to water or weed. It will keep the soil evenly cool and maintain a constant level of moisture plus a little organic nutrition. Granulated Bark (especially Cedar, Cypress or Oak or Pine), Peat, Pine needles, crushed Oak leaves among others all make great acidic mulches because they are organic and acid pH.
Pieris are best planted in dappled light or semi-shade and are often right at home in eastern morning sunlight. Avoid dry, hot, highly sunny, windy sites that could dry-out or scald the new foliage. They are most effective in a Japanese or woodland garden, shady border, shrub and tree garden or as an exquisite container plant. They are often used as a foundation planting in the shadier corners of a house or near a garden structure.
While this is often where they thrive the best, there are many examples, as mentioned earlier of Andromeda and Pieris planted right out in the open and creating stunning features. The secret is in finding a location with those ‘perfect’ conditions they need. Once they have that, these are effortless to grow and extremely rewarding flowering ornamental shrubs/
Pieris species vary in size from 1-6m/3.3-19.7ft and are quite compact and spreading shrubs 3-10ft/1-3m wide or more. They usually create a branching but fairly dense round to oval-shaped canopy. Most are smaller to medium sized evergreen shrubs 3-8ft/1-2.4m. This is especially true with most Pieris japonica cultivars: they are rather small, slow growing and very well behaved. So are the larger species. A few can eventually grow up to create highly ornamental small trees
Pieris japonica 3-8ft/1-2.4m is often used to create exquisite Bonsais as it will easily dwarf and responds well in containers. For this reason, Pieris are often used in raised landscape planter boxes and terraced garden which stay fairly cool and somewhat shady. Provided they receive the constant humidity and regular watering they need, they can thrive in a containerised environment for many years. Their habit of growth often becomes stockier with more abundant flower clusters when their root system is somewhat confined and restricted.
Pieris can be planted almost any time from well-established container plants. But by far the easiest time to plant is during the cooler and wetter months: usually Mid/Late Autumn through Spring. Late Winter and Early Spring being perhaps the most preferred. This way, it is possible to see the shrub’s emerging flowers and a little of its new colourful foliage before choosing its final planting location. That way, it can be ideally positioned in just the right spot so that its colour and form compliments the rest of the garden. Pieris can be difficult to shift once established so choose its planting position carefully.
Make sure that its planting hole is at least twice as wide as its root ball and at least half as deep. If there is any question about the soil pH and quality, amend the soil before planting. To amend soils with a higher than ideal pH, sprinkle Flowers of Sulphur powder into the planting hole. Or alternatively add a handful of a commercial fertiliser especially suited to feeding Azalea, Camellia, Daphne and Rhododendrons. Some Gardeners prefer to added crushed Oak or Pine needles into the hole. Peat and well aged manure or light and fluffy compost can also be mixed in. This is especially helpful in sandy land to improve its water-retentive capacity and enhance its enrichment.
It is always best to dig in all fertilisers and soil amendments first. Then water them in and allow the land to ‘cure’ for at least a week or longer before planting the shrub. This avoids the chance that ‘hot’ chemical salts or organic acids might burn and damage emerging new roots.
Plant the shrub at the same level as it was growing in its container or just a fraction deeper. When planted from bare-root or balled-and-burlap, plant so that the top of the root ball is about 1-2in/2.5-5cm below ground level. Fill in around the root ball carefully to ensure that no air pockets remain that might dry out the roots. Water in thoroughly and add acid mulch at that time to help maintain an even supply of moisture to the new shrub. Water regularly until the shrub appears to be well established. Watch carefully especially the first Summer and Autumn after planting or whenever weather remains dry. It is best to frequently mist over the foliage or water lightly and regularly rather than wait until wilting occurs from drought or heat.
Usually newly-planted Pieris do not need staking. They are best grown in positions that are not very windy and usually the plants are rather small and stocky when first planted. The exception might be the taller Andromeda-type Pieris species. If the shrub is more than 3.3ft/1m tall and exposed to frequent winds then consider staking.
Pieris can be grown successfully from seed, gathered and planted immediately in Summer and Autumn. This often germinates when placed into light and porous potting mix or seed raising mix in a pot or seedling flat. Or place this in a cold frame and let it remain there to stratify over the Winter. Seedlings usually emerge the following Spring. Alternatively the seed can be placed in damp paper towelling in a closed plastic bag. Place this in the refrigerator for 4-6 weeks to simulate cool wintry conditions and then sow the seed. Seedlings will usually come into their first flowering 3-5 years after sowing. This is how new hybrids are created.
Cuttings can be started from mature wood taken in Late Summer and Autumn. Use healthy and strong top growth 4-6in/10-15cm lengths. Pinch out the growing tip or emerging flower buds. Optionally dip into hormone gel or powder. Place (if hormone gel is applied) or plunge into porous potting mix or seed raising mix and place in the bright and humid cold frame. Small plants should be ready to transplant into small pots or a nursery row late the following Spring. Semi-mature new growth can also be started in a propagating box through the Late Spring and Summer months.
Alternatively, Pieris can be started from layering of lower branches. These can be nicked with sharp secateurs then the nicked place on the lower stem is pinned to the ground or securely anchored with a stone placed over the top of them. This can be done almost any time but usually works fastest when started in Late Summer and Autumn. The new layered cutting should have produced new roots by the following Spring and can be cut away from the parent then and repotted. Most such cuttings are ready to plant out within about a year.
Pieris is a real ‘pearl’ of a plant. It is beautiful all year, especially when in full flower. And its dramatic and rich foliage colours add a real sparkle of interest to almost any garden border. Its durable, handsome and hardy qualities make Pieris a garden pearl well worth treasuring!