UNITED STATES—Even without significant cool weather, the garden knows that it is now autumn. Most of the late summer blooming flowers are finishing their last bloom phases. Leaves of some of the deciduous trees, shrubs and vines are already changing color, and some are already falling. Perennials that are dormant through winter are already starting to deteriorate.One of the several difficulties of living in a climate with so few difficulties is that autumn and winter weather is so very mild. Just like so many warm season annuals and vegetables want to continue to perform when it is time for them to relinquish their space to cool season annuals and vegetables, many other plants that should go dormant in autumn really want to stay awake as long as they can. Some semi-deciduous perennials even start to regenerate new growth before they shed their old growth.
Where winters are cooler, such plants generally shed the growth that developed in the previous year, or in other words, they ‘die-back’. They then stay dormant through the coolest part of winter, to break dormancy and regenerate late in winter or early in spring.
Beard tongue (Penstemon) can really look bad as the last flower spikes deteriorate, and the foliage gets spotty and grungy. It will be tempting to cut them back early. If possible, it is better to only prune off the deteriorating flower spikes, but wait until later in winter for major pruning. Premature pruning stimulates premature development of new growth that does not mature as well or as fast through winter as it would in spring. Such growth can be discolored, sparse and less vigorous until it gets obscured by later growth.
Marguerite daisy, ginger, canna, some salvias, most begonias, the various pelargoniums and all sorts of other perennials will likewise seem to be rather tired this time of year and through winter, but do not necessarily need to be pruned back just yet. Simply plucking or shearing off deteriorating flowers should be enough for now. Ginger and canna should not need to be pruned back until the foliage deteriorates enough to be almost unsightly. Begonias and pelargoniums, particularly common zonal geraniums, will be better insulated from potential frost damage through winter, and may not produce so much sensitive new growth if not pruned early.
Highlight: Beard Tongue
With such a weird name, beard tongue is probably less commonly known by its common name than by the Latin name of Penstemon. Of the thousands of cultivars (cultivated varieties) that have been developed over the decades, most of those that are popular for home gardens are known as cultivars of Penstemon gloxinioides, even though their actual lineage is generally unknown. In recent years, other species have become more available.
Spikes of red, pink, purple or white flowers stand vertically above the foliage. Yellow flowers are still rather rare. Individual flowers are bisymmetrically tubular, with two conspicuous lips and a fuzzy tongue. Some beard tongue have relatively wide leaves and plump flowers, like really big snapdragons. Others have narrow leaves and thin flowers. Mature plants get only one to two and a half feet high and a bit wider, although some of the rare specie can get significantly larger.
By Tony Tomeo