The gentle art of pinching

Sunday, 07 September 2014

Fuchsia cultivar that has been tip-pinched

Now, I am not talking about stealing cuttings (though I do sometimes indulge in this morally dubious pastime when I am out walking, only taking bits of plants that are hanging over fences, not actually reaching inside of anyone's garden, I promise) but about pinching out the growing tips of my plants. It is something I have rarely done in my gardening life but I got interested in it recently when I was running a workshop on plant propagation and found myself recommending this as a way of producing good-shaped plants for a stall I am involved in later in the year.

Salvia semiatrata which has been tip-pinched several times to produce a more compact plant

The idea is to make a more compact plant by pinching out the growing tips. This forces the plant to produce two new shoots at that point. Successive shoots can also be pinched back, so that the result is a much fuller, stockier plant instead of a gangly, lanky specimens (like so many of my plants are!). The science behind the idea of pinching in this way is that removing the shoot tip breaks its 'apical dominance' such that dormant side buds in leaf axils lower down the stem are stimulated into action.

Coleus is one plant that will benefit from tip-pinching

It takes hardly a second to perform the action, but the results are very much worth it. No fancy equipment is needed - just your thumb and forefinger. Some plants that seem to benefit from this method are all sorts of Fuchsia types, zonal and scented Pelargonium, Dahlia, many Acanthaceae plants such as Justicia species, Odontonema and Ruellia species and many Salvia. Annual flowers such as pansies, petunias etc will also grow into much more compact shapes if tip-pruned in their early stages, as will annual herbs such as basil. Soft-stemmed foliage plants such as coleus, Iresine and Alternanthera will also have an improved form if pinched back. The best time of year is during periods of active growth in spring. The technique should not be done as the plant approaches its flowering time, but with judicious pinching having been done, the plant should have a lot more flowers than if left to its own devices. Regular feeding during the time of pinching out will help encourage lots of new growth. Giving evergreen shrubs and hedges a light, overall trim at this time of year is really another form of tip pruning and will also promote denser form.

Abutilon can be shaped into a standard by training to a single stem and tip-pinching the growth

When pinch-pruning is repeatedly done to plants, it will produce much bushier growth. The technique is useful in creating a standard plant trained to a single stem with a nice rounded head - suitable plants can include Abutilon, Marguerite daisies, heliotrope or even coleus! Some gardeners extend this method employing wire frames and stakes to produce more exotic shapes - this is often done in Japan with florists' chrysanthemums and other plants to make huge spheres, pillars, fans, cones and even poodle-like forms!

Tip-pinching is such a simple idea yet it has the potential to make our garden plants look so much better! I'd love to know whether you have ever tried this method.