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Plants in garden
Climbers
Celastrus orbiculatus - oriental bittersweet

Climbers

Growing climbers

Apart from clematis, there exists a large group of climbing vines worth popularising. Climbers take up little space in the garden all the while giving a spectacular display owing to the mass of greenery they produce: Silvervine Fleeceflower (Fallopia), Dutchman’s Pipe (Aristolochia), Oriental Bittersweet (Celastrus), Trumpet Creeper (Campsis), Vitis, Parthenocissus, Monks Hood Vine (Ampelopsis), Actinidia, beautiful flowers: Wisteria, Trumpet Creeper (Campsis), Honeysuckle (Lonicera) and ornamental fruit: Oriental Bittersweet (Celastrus), Nightshade (Solanum), Ampelopsis, as well as edible fruit: Actinidia, Magnolia Vine (Schisandra) and Akebia. The majority of climbers climb by twining spirally round the support, while others, owing to the presence aerial rootlets e.g. Ivies (Hedera), Climbing Hydrangea (Hydrangea anomala subsp. petiolaris), Trumpet Vine (Campsis), Japanese Hydrangea Vine (Schizophragma hydrangeoides) and Wintercreeper Euonymus (Euonymus fortunei), or adhesive tendril tips, e.g. Japanese Creeper (Parthenocissus), are self-clinging and can scale a flat wall, without added support.

Climbers are particularly useful for covering outer walls of buildings. Apart from their decorative aspect, they also act as insulation during winter, and retain a pleasant coolness inside the house during hot summer days. They also help keep the walls dry by shielding them from the rain, and draining excess water away from the foundations. Creepers are best suited to this end, but you can equally well use ivies or Trumpet Vine, or any other climber on condition that a suitable support is provided.

Climbers can cover unsightly buildings, sheds, warehouses, rubbish sheds, etc. hiding them quickly from view. If you want to have the effect in just one year, you should try Silvervine Fleeceflower (Fallopia aubertii), Hop (Humulus), on clematis belonging to the Tangutica Group e.g. 'Bill MacKenzie' or ‘Lambton Park’ or alternatively, Clematis'Paul Farges' of the Vitalba Group. If you can wait 2-3 years, you can use any climbing vine described in this section.

Climbers can grow up various kinds of fences (np. siatki) (e.g. wire meshes). They will not only provide decoration, but will also screen us from nosy people's eyes and protect us against winter and dust. The following plants are excellent for this purpose: Common Ivy (Hedera helix), Japanese honeysuckle (Lonicera acuminata), clematis of the Atragene Group (especially 'Pamela Jackman'), the Tangutica Group (especially 'Lambton Park'), the Viticella Group (especially 'Etoile Violette' and 'Polish Spirit') and the Vitalba Group (especially 'Paul Farges'), Monks Hood Vine (Ampelopsis aconitifolia), Virginia Creeper (Parthenocissus quinquefolia) and Boston Ivy (Parthenocissus tricuspidata).

The majority of climbers don’t require any special soil conditions, but since they produce a large mass of greenery, they don’t like very dry and poor soils. Heat-loving species, such as actinidias (Actinidia), wisterias (Wisteria) and trumpet creepers (Campsis), prefer warm, sheltered and sunny sites, while Common Ivy (Hedera), Climbing Hydrangea (Hydrangea anomala subsp. petiolaris), Dutchman’s Pipe (Aristolochia), Schizophragma (Schizophragma), Wintercreeper (Euonymus fortunei), Akebia (Akebia), Hop (Humulus) and some honeysuckles (Lonicera) will feel better in a cooler, shaded and moist site.

When planting climbers dig a hole of 50x50x50 cm and fill it with fertile soil. Depending on the species, put the plant 0-10 cm deeper than it used to grow in a pot, at least 30-50 cm away from the wall and 50-100 cm away from the trees. Well chosen and correctly planted climbers can grow for many years, decorating your garden all year round and providing excellent shelter for birds.

Oriental bittersweet is the most valuable climbing plant with ornamental fruit. It is generally hardy, undemanding and vigorous in habit, which makes it well worth of any gardener's interest. Celastrus is a member of the Celastraceae family.

There are around 30 species belonging to this genus, native mostly to subtropical regions. A few of them are capable of enduring polish climatic conditions, but only Celastrus orbiculatus - Oriental bittersweet is universally used.

Celastrus orbiculatus (photo Sz. Marczynski)

In some collections you can also encounter Celastrus scandens - American bittersweet, a similar species from the same genus. Both species have vigorous twining stems and are dioecious. They bear inconspicuous, white to greenish flowers, gathered in clusters. Fruits appear only on female plants pollinated by neighbouring male specimens. Rounded yellow three-valved capsules split open at maturity to reveal closely packed seeds completely enclosed in fleshy red or orange arils. Upon ripening the yellow outer covering contrasts beautifully with the red or pink inside. The fruits stay decorative for several months and make an excellent addition to dried flower arrangements or interior decoration.

Celastrus orbiculats - Oriental Bittersweet is native to Japan, China, and Korea. It grows very vigorously attaining the height of 12 m (1-4 m of new growth a year). The stems are covered with numerous small axillary buds with spine-like outer scales. Rounded or elliptic, finely toothed leaves turn bright yellow in autumn. The flowers are usually gathered in leaf axils.

Celastrus orbiculatus (photo Sz. Marczynski)

Two varieties are encountered in cultivation:

'Diana'- a profusely fruiting female clone (it sets fruit only if there's a male clone in the neighbourhood that can pollinate its flowers).
'Hercules' - a male clone, a good pollinator for female plants, also for 'Diana'. It ensures abundant fruit crop. It can grow separately from a female plant and is widely used in places where berries are not welcome, for instance in children’s gardens or along the roads outside the city boundary.

Celastrus scandens - American Bittersweet is native to northern America. It's less rampant than Oriental Bittersweet - it attains the height of about 7 m. It's not popular in Poland, as it rarely sets fruit in our cool climate. Flowers appear in terminal panicles, which distinguishes it from C. orbiculatus.

Requirements.
It can grow in all types of soil, including drying soil. It's better to plant it in poor soil, as in the fertile one it can become too expansive. Well adaptable to different levels of pH of the soil. Tolerates half shade, but thrives and yields best fruit in full sun. It's frost hardy and only rarely affected by pests and diseases. Responds well to pruning.

Celastrus orbiculatus over the entrance to the block of flats in Warsaw's district Ursynów (photo Sz. Marczynski)

Application.
Ideal for public open spaces. It is well suited for covering tall fences, solid structures (arbours, pergolas, arches, unsightly buildings etc.), and makes a good plant for creating noise barriers along roads and motorways. It looks interesting when climbing up old tree trunks or large trees. Due to its rampant growth, however, it shouldn't grow next to bushes, small trees or conifers as it may choke them up. It may also grow in large containers on balconies or terraces, if you want to create a green screen. If grown in a suitable place and kept in check by pruning, it will adorn any garden without posing any threat to other plants.

You should only buy vegetatively propagated plants from a reliable source, as only such plants will grow best and yield fruit. Avoid purchasing seed-propagated plants of unknown sex, so frequently encountered in commerce.