Around the Garden with Busy Lizzie - September

When I walked out in to the garden this morning, I found we had been visited by a frost – granted, a very light one, but a frost nonetheless.

I don’t know why I was surprised.

This is, after all, the month which issues a change in our weather and one where you would expect to find things becoming a little chillier.

I expect the recent spell of decent weather lulled me into a false sense of security, which is why I had left some very tender plants outside and why they are now looking a little unhappy.

To keep or not to keep, that is the question facing many a gardener at this time of year.

Many of our tender perennials are only just getting in to full swing and many have a lot more to give, provided that they are not subjected to inclement weather.

If we do bring them in to the house or greenhouse, they will need looking after and things like compost, heating and the like do not come cheap these days.

Most can be replaced with new, fresh plants next season which will require the minimum of fuss.

However, anyone who has over-wintered a favourite plant will know that it is more than worth while to do so.

One is rewarded with larger plants which are quicker in to their stride and in flower weeks ahead of their younger comrades.

Should you choose to keep your plants, there are a few tasks to be completed now if you want them to remain in the peak of health.

Firstly, those plants which still have a lot of flower to give will probably keep going for most of the winter if brought in now.

If they are already in pots,they will appreciate a top up of fresh compost, a high potash feed such as tomato food (which will promote flowering) and a general pick over to remove faded blooms and leaves.

In some cases, it is worth re-potting the plant completely and you will know if this needs to be done as the leaves will be yellowing and roots may be protruding from the drainage holes at the bottom of the pot.

Choose a free draining compost such as John Innes No. 2.

If you are lifting the plant from a larger container or the border, water well 24 hours before and try to get the plant out with as much soil (and hence roots) as possible.

Pop it into a fairly close fitting pot, which will keep it happy without promoting too much sappy growth, and water again which will help the plant to establish itself in its new home without too much stress.

There is a slightly different approach to keeping the plants which you wish to retain for a display next year.

Allowing them to continue flowering will only sap the plants energy so they should be stopped now.

Remove all flowers and buds and nip back all excess growth, at the same time removing spent leaves and tired stems.

Any healthy, green-stemmed shoots can be used as cuttings.

Select healthy growth around 4 inches long, remove the lower leaves and any flower buds and pinch out the growing tip (anything preparing to flower is unlikely to root).

Insert around the edges (where rooting seems to be more successful) of a small pot filled with free draining compost (a 50:50 mixture of multi-purpose compost and perlite is ideal).

Water and allow to drain then position the pot on a windowsill where there are good light levels.

The addition of a little heat, supplied by a propagator, will speed things along.

Keep the compost just moist and then increase in late February to encourage growth and ‘Hey Presto’ a new plant.

It is possible to completely strip the parent plant for cuttings and then it can be popped under a greenhouse shelf and that too may come back next year, given the same feeding and watering regime as its babies.

This system also works well with semi-tender perennials such as Penstemons, Salvias, Lemon Verbena etc. Cuttings are the only way of ensuring that you get the same plant as its parent.

Plant breeding has reached such a degree that there are so many new varieties and colours of plant on the market each year that the older ones, which you may have developed a liking for, are often superceded.

This way, you can hold on to a good supply of a plant which you know does well and flowers in the shades that you want.

When considering retaining the parent plant it is worth considering one or two things.

If you want it to flower, then it will require heat.

Often a windowsill is enough but a heated greenhouse or conservatory is ideal.

If the plant has heat it will also require water, just enough to moisten the compost and only when it has completely dried out.

Check regularly for signs of disease and remove the offending article promptly.

A layer of grit on the top of the pot often helps against rot.

Closely packed plants also invite insect infestation – I have a dreadful white-fly problem in my conservatory which is dealt with with the use of a non-chemical spray and yellow sticky traps hung around the place – okay for catching the pests but not nice when your hair gets stuck to them!

Popping the plant outside on a mild day will help to refresh it and will go some way to combating the stress which these plants suffer from when asked to keep going out of season.

A little high potash feed will not go amiss and regular dead-heading will promote further flowering.

Of course there are those who simply chuck their spent bedding Pelargoniums under the shed wall and retrieve them the following year seemingly none the worse for wear.

I found an Abutillon which I thought had died growing quite happily at the back of the compost heap and flowering its silly head off.

I have potted it up but I am sure it would have been just as happy where it was, but I am not prepared to take the risk.

I am, sad to say, quite emotionally attached to some of my plants and could not bear the thought of losing them.

Besides a lot are rare and some are valuable, which makes it all the more important that I try to over-winter them successfully.

Some plants which it is worth trying to keep in flower over winter include Zonal and Regal Pelargoniums, Abutillons, Felicias, Argyranthemums, Osteospermums and Salvias (particularly the scented-leaved varieties).