The plant featured in this article is a rather an unusual species to be used for bonsai, Perovskia atriplicifolia or the 'Russian Sage' is a deciduous perennial more commonly seen growing in the garden flower-border.

I should say from the outset of this article that I would not recommend this species for bonsai; it is a fast-growing but relatively short-lived plant that suffers badly from dieback each Winter. However, with this tree I do think it is worth illustrating the short term pleasure that one can have with other similar fast-growing but short-lived and therefore 'unsuitable' species.

Despite its common name, P. atriplicifolia is native to Afghanistan. It is known as a 'sub-shrub'; a perennial shrub that is fully hardy but produces weak woody stems that frequently dieback to the ground during the Winter months (depending on the severity of the cold). As it is the below ground portions of the plant that are hardy, sub-shrubs have a strong tendency to produce many short-lived stems (or suckers) rather than one dominant trunk. Other common sub-shrubs include species such as lavender, thyme, heather and some fuchsias.

Sub-shrubs do have some useful characteristics; with an annual cycle that sees them growing many new stems('trunks') and branches and flowering prolifically all in the space of 4 or 5 months, sub-shrubs are very fast growing and very responsive to pruning during the growing season. They also have a tendency to have strong 'lifelines'. If a branch is removed, its entire sap-line back to (and including) the roots that supported the life growth, die back producing many interesting and natural shari.

Perovskia atriplicifolia itself produces grey-white shoots with deeply cut green-grey leaves and violet-blue flowers in tall panicles up to 12" tall in late Summer and early Autumn. Older wood develops a rough and flaking bark that creates a good impression of age after just a couple of years. One of Perovskia's best attributes is that if pruned or even slightly bruised, the leaves and the stems give off a pungent Lavender odour. As with most sub-shrubs, it is very fast growing.

In summary, sub-shrubs are not great for bonsai; while the base can live for a number of decades, any trunks that do form will rarely last more than 5-10 years and younger growth used for branching is very susceptible to dieback in Winter. Purposely developing such a species in the ground from a young nursery plant would be a very frustrating exercise; however, if the opportunity arises to use a large and interesting trunk dug up from the landscape, it doesn't hurt to try and create something a little unusual.

February 2006: this Perovskia had been growing in my garden for 7 or 8 years but was eventually removed to make room for other trees and shrubs.

Once dug up out of the ground, it seemed a pity to just throw or give away a plant with such a compact rootball and interesting trunks so I grabbed my camera, took a few pictures for posterity and decided to see if anything in the way of bonsai could be developed.

February 2006 continued: this tree was approached in the same way as with designing all bonsai. The trunk or trunkline(s) are paramount. The trunk(s) are at least mentally established before you even consider the branching. It is of no use to prune the raw material back so that it has great branching and a horrible trunk.

Great branching can be grown on a great trunk. A great trunk cannot (or can rarely) be developed without making a mess of great branching.

In my minds eye I could see that by turning the tree a little clockwise, I could produce a single or multi-trunked semi-cascade bonsai as can just be seen in the image above........

.........but not in this final 'potted up' image. For some reason I can only find an image of the back of this tree at this stage and not one of the front.

Prior to potting up the tree, the roots had been completely bare-rooted to remove all ground-soil before being planted into an inorganic soil mix. This is essential.

June/July 2006: The result of the hard pruning in February was prolific budding from the trunks when the tree started into growth in April. By the end of June I had been able to establish which of the 'trunks' had made it through the Winter without dying. The image above shows the tree after a second styling; several live trunks had been removed and the current years growth had been either removed or pruned back very hard.

Such is the speed of growth with this plant that within days of hard pruning and taking this image, the tree was responding with new buds and shoots.

For the remainder of 2006 (just its first year after collection from the garden) the tree was repeatedly grown and pruned back to develop the new branching and foliage.

During the Winter of 2006, further refinement of the structure was carried out and the number of live trunks was reduced to just one; the cascading trunk. Perovskia, as with most sub-shrubs, have poor callusing characteristics and so when branches are removed they are shortened to stubs and jinned. Each of these stubs needed to be carved as can be seen in the close-up of the cascading trunk above.

Rear-view of the cascading trunk showing the natural shari that developed after removal of two branches.

July 2007: In early Spring the tree was planted into a beautiful blue crescent pot from Erin Pottery. By July there had been more than enough new growth to build a small pad of foliage on the end of the one remaining cascading branch.

And the future of this Perovskia bonsai? Who knows. It has been quick to develop and could be as quick to die-back and be rendered un-usable as a bonsai. While the core of the plant (the base) will without doubt continue to produce suckers and new growth for a good few years to come, the cascading trunk will have a limited lifetime. One Spring in the next few years I will find that the trunk fails to bud out and the temporary image that I have created will be lost. But in the meantime, I'll enjoy it as it is.