September in the Garden

In those rare years when the summer has been unusually hot and dry, with water restrictions and parched soil, the beginning of autumn can be a blessed relief. This year is not one of those, despite the notably high temperatures, with a lack of rain, early in the season, but it’s still a turning point in the gardening year. Shortening days and cooler temperatures, allied with higher rainfall, makes September a good ‘doing’ month. It can be thought of as the beginning of the gardening cycle, a ‘second spring’, because a lot of sowing, planting and general garden making can resume after the summer pause in horticultural activity.
Chief among the tasks which can begin now, with gusto, is planting spring flowering bulbs. This is a really positive, life affirming, endeavour and, rare amongst gardening practices, comes with practically guaranteed flowering success. Technically, bulbs are known as ‘perennating organs’ i.e. the means for a plant to survive from year to year especially when that involves overcoming unfavourable, seasonal, growing conditions. In the case of bulbs, the unfavourable conditions that evolution has needed to overcome is, most commonly, a lack of water, during a certain period of the year, in the native climate where that plant species naturally occurs.
In the northern hemisphere the time of year which has the highest temperatures, hence lowest rainfall, is the summer. Spring flowering bulbs are therefore ‘programmed’ to be dormant in the summer, which is why they are not visible above the soil surface, and are triggered back into growth by the cooler autumn temperatures plus the relative abundance of rainfall. The complication here is that the initial growth, triggered now in the case of spring flowering species, is root growth. For obvious reasons this is not visible to the humble gardener, unless you dig them up; a case of ‘out of sight, out of mind’.
In autumn flowering bulbs and corms, less common than the spring bloomers, flower production is the first thing that is triggered so these will already be providing a show in the garden. To this end, I often find that the indispensable little Cyclamen hederifolium (‘Ivy leaved cyclamen’) starts sending up its cheerful blooms as soon as there is heavy rain after a spell of summer heat. It’s been flowering in my garden for a few weeks now, a little fitful at first, and will continue to do so right through the autumn. The leaves appear after the flowers, in fact they overlap for a while, and persist right through until summer next year.
Cyclamen are one of those obliging garden plants which will quite happily seed around, forming large colonies over the years, but are never thuggish enough to become a problem. They are easily dug up, replanting them somewhere else, if they seed into areas where they are not welcome. They also have the bonus of attractive foliage, often sporting strikingly ‘marbled’ variegation, so that even after flowering they make a positive contribution to the garden. Together with their ability to provide winter ground cover, even in shady positions, often under deciduous trees and shrubs, it’s hard to see any downside to these hard working garden plants.
Returning to planting spring flowering bulbs; the priority here is to get them into the ground as soon as possible after they become available by mail order, most easily achieved these days via online shopping, and in the garden centres. The bulbs offered for sale are grown as crops, most famously by Dutch nurserymen, and will have been harvested at the peak of their summer dormancy. The smaller the bulb the quicker it will dessicate, losing its viability, post-harvest. Often it is the smaller bulb species which are the earliest to flower in the spring, e.g. crocus and iris species, so it makes sense that these should be your priority when it comes to their autumn planting.
Running the risk of getting waylaid by another horticultural anomaly, at this point I need to make a mention of snowdrops. Given that snowdrops are commonly perceived to be the earliest of our spring flowering bulbs, surely we should commence bulb planting with this iconic beauty? Hmmmm……….snowdrops are the ‘exception that proves the rule’. They are recommended to be planted ‘in the green’. This simply means that they are best obtained, from commercial suppliers, immediately after flowering, while they are still in growth, replete with their full deployment of leaves. They are more likely to establish in new planting positions if transplanted this way rather than obtaining them as dormant bulbs.
This is, reassuringly, a confirmation of the theory that it is the smallest bulbs which dessicate the fastest once dug up. Snowdrop bulbs are so small that, if purchased as dormant bulbs in the autumn, there is a high probability that a proportion of your new bulbs will already have dried out and they will fail to grow at all. To all intents and purposes they are dead. There is also a good chance that any snowdrop bulbs offered for sale in the autumn will have been harvested many months before, due to their very early blooming, and therefore will have already been out of the ground, perhaps in less than ideal storage conditions, for much longer than the ‘main season’ bulbs.
When it comes to obtaining spring flowering bulbs, the internet is a real boon when it comes to choosing species and varieties for your garden, pots and bedding displays (does anyone actually plan ‘bedding displays’ anymore?). The ability to see colour images, together with full descriptions, of everything that you are buying makes choosing spring bulbs so much easier than when you had to leaf through catalogues, often with only written descriptions to assist you, and then fill out order forms. Having said that, there is still a lot to be said for physically going to a garden centre, as soon as they put their bulb displays out, in order to fill a bag with your favourite bulbs and to get the buzz of instant gratification.
With all that bulb talk I’ve almost run out of room for all the other gardening tasks which should be undertaken at this pivotal time of year. Off the top of my head I’m mostly thinking that lawncare should be done now while the soil is still warm but rainfall is more reliable. Hardy annual seeds should be sown so that the seedlings can get established before winter cold halts their growth. Beds and borders will require some intervention to remove collapsing foliage and to edit them sufficiently to make the most of the autumn flowering constituents. Hedges, especially evergreen ones, should not be cut much later than September as they require a little time to recover before they are hit by the first frost.
Obviously, there’s quite a lot of gardening activity that can be undertaken now that summer is over—although it’s always nice to think that we might have some balmy weather which continues long into the supposed autumn!