Decorative, original and elegant, stem shrubs can play a key role in exteriors of different configurations. These small trees are a plant creation that is used more and more by landscapers, and is particularly valued in nurseries and garden centers. Here's how to make them, maintain them and stage them.
What is a shrub on a stem?
It is a plant (a evergreen or deciduous shrub, a climbing plant or sometimes an indoor plant) specially shaped by a nurseryman or even by a lambda gardener, to form a single stem at the end of which develops a bushy head of foliage and / or flowers; this head can be cut into a ball shape, or left more free, or in 'weeping' shape. The shrub on stem is easily identifiable by its slender silhouette and its 'well made' head (as Montaigne would say!); after a few years it looks like a miniature tree. There are three main categories: - the classic version : a shrub cut to form a single stem, 60 cm to 2 m high, - the grafted version , rarer, however, and above all used for stem roses, - the "persistent" version for yew and boxwood, which are often intended for topiary art. The shrubs on stem are real decorative shrubs, which find their place in all gardens. It is also a 'gift plant' increasingly in demand in garden centers.
One stem, variants
'Rod' and 'half-rod', straight, spiral and even double! The half-stem shrubs reach 60 cm to 1 m or even 1.20 m, while their elders can go up to 2 meters - then getting closer and closer to the real small tree. Often straight, the stem can also be spiraled - like that of the bay laurel or the olive tree led into shrub stems. "To obtain this result, explains the nurseryman Damien Ripaud, we plant in a tray a strand of the chosen plant, smaller than the little finger to be very handy, and we grow it quickly, around a stake for 2 to 3 the trunk enlarges and then keeps this shape when the stake is removed. The 'must' with a spiraled trunk today are laurel tin (viburnum tinus) and wisteria, the latter of which can even be mounted on two rods, wound to create a braiding… achievable in 3 to 4 years.
Which plants and flowers are best suited for this?
The range of possible achievements is very wide and many plants can be in the form of shrubs on stems. Historically, roses and citrus fruits are the ancestors of this current trend - orange and lemon trees were once used in orangery bins for their 'exotic' effect. However, the boom linked to the success of stem shrubs is quite recent, linked to their use in small gardens especially. One of the best-known stem shrubs is perhaps the oleander, as well as, among the topiaries, boxwood, yew and privet - for a 'French' style. Among the weeping stems, the stars are the cotoneaster, the willow marsault and also the prunus-cherry trees. But many others can be erected on stems, such as photinia, azalea, mimosa, lilac, hibiscus, camellia, buddleia, cypress, eucalyptus, osmanthus and even currant . "Even hydrangea paniculata hydrangeas can be grown as stem shrubs, emphasizes Damien Ripaud, breathtaking effect!". He also advises solanum rantonnetii, polygala and callistemon: vibrant blooms even more enhanced by this tall form. Finally, it is also possible to make a stem shrub with a dwarf umbrella pine, Japanese maple, honeysuckle, bougainvillea, holly ... And even a daisy! The shrimp willow is a star of today's gardens.
Shrub on stem: what advantage in a garden or on a balcony?
The shrubs on stem can structure a green space, give height to the beds and create volume. "We rather plant them near the house, explains the landscape gardener Benoît Cossenet, a landscape gardener labeled Jardins d'Excellence, because their spectacle is pleasant - we will also reserve the bottom of the garden for a more 'natural', less sophisticated atmosphere". They can also define an aisle if they are planted in alignment and thus accentuate the perspective. But above all, the shrubs on stem are particularly interesting in small city gardens, where they then become a flagship element because they create the illusion of large subjects while freeing up space at ground level ... Finally, on balconies and terraces, in pots, they are decorative as desired, especially if they are embellished with plants at their base (helxine, ground cover, perennials ...).
Are the shrubs on the stem fragile?
Since they are horticultural (therefore artificial), some shrubs on stems may indeed require more attention. First of all, it depends on the type of plant to which this noble form has been given. The oleander for example, like the callistemon polygala (which are Mediterranean plants), will have to be wintered in the northern regions, whereas a boxwood will be able to spend the winter outside. "In addition, if their head is too heavy, it can get caught in the wind, risk dropping the plant, and damage it, warns Benoît Cossenet. Consider staking if your plant grows quickly and seems unbalanced to you." Likewise, if the stem is young, it will appreciate the help of a tutor.
Shrub on stem: pruning and maintenance
Above all, watch that young shoots do not form at the base of the plant, so as not to change its appearance and weaken the shrub at the top. The subjects in tanks must also be watered often and nourished thanks to contributions in fertilizer (especially K if the plant is particularly fragile); a drip system can be installed if you do not have the time to take care of them. Pruning can be frequent or occasional, but always essential for the shrub to retain its haughty shape: "Every year only if you want to give it a really regular shape, advise Benoît Cossenet and Damien Ripaud. The topiaries will specifically need a "French" size, 2 to 3 times a year. Conversely, the cotoneaster or the hibiscus will be left to create their own original shape. , it has a special size: it is better to cut it short because this vigorous plant needs to be contained in a reasonable size ".
It's your turn !
If you want to get started, choose an easy-to-make plant on a stem: fuchsia or solanum for example. Choose a vigorous branch on the plant that will form the trunk of your homemade shrub in a few years. Plant it in a very large container and cut off as and when all the branching branches grow, while feeding it enough so that it finds the strength necessary for its good growth. Regular repotting can also be beneficial. In a few years, you will obtain a magnificent shrub on a stem! Marry several in a pot for a nice setting, and play on the different levels of vegetation to create a harmonious picture. Thanks : - Benoît Cossenet, garden designer: www.cossenetbenoit.com - Gardens of Excellence label: www.jardinsdexcellence.com - Ripaud nurseries: www.ripaudpepinieres.com