Growing gladiolus from seed is something that I hadn't really thought about until last year. Looking through various gardening catalogues some while ago; I came across a plant called Gladiolus papilio 'Ruby'; this rang a bell in my head but I couldn't quite fathom out why. I know the straightforward Gladiolus papilio, it has slightly odd flowers that are hooded and have the appearance of not quite opening properly however, this is its habit, you either like it or you don't.

Its colouring too is odd, flowering in a combination of cream and dull purple, you will either find this the height of sophistication, or funereal, I still can't make up my mind! I was looking up the straight forward G. papilio when quite suddenly, I remembered that I had read somewhere about its rather lurid colouring but, that it had a cousin with much brighter, richer flowers of a good rich-ruby red but, still retained the hooded shape of its cousin. The description said that it grew to 1.2 metres (4 feet) tall, relished a position in full sun with good drainage so I bought five pots of bulbs that were, I thought, quite expensive at �4.55 per pot.

As it turned out, I need not have worried too much for the pots were full of bulbs and each pot produced at least three flowering stems in their first year, I began to realise that you sometimes do get what you pay for!

I planted these in the south facing, narrow border in front of the new fence that lines the entrance to the garden and here they prospered behaving exactly as the nursery said they would but there was an unexpected advantage. After flowering I left the seed heads on because I thought them quite decorative and when they opened were quite obviously full to bursting with seed, I quickly harvested them, Ian sowed them straight away in seed trays and they germinated within two weeks.

This was cause for great excitement, for the seeds had appeared to be very papery and thin and not in the least fertile. How wrong can you be? These have been growing steadily, albeit slowly, in our propagating house and I shall look forward to planting these in them in the garden in spring. It will probably be two to three years before we get any flowers from them but, they have cost us very little and if we wish to grow them in any quantity this would seem the ideal way in which to bulk up our stocks quickly. As well as being easy to grow from seed, I believe that they readily increase underground making masses of cormlets too, again something to look forward to!

I would like to grow these for picking for they are quite unlike the ordinary gladiolus that is usually seen, although they share the same habit of needing their dead and dying blooms being removed from their lower stems as they go over. A large vase of the plain funereal G. papilio and her more colourful cousin 'Ruby' together would look very nice for the one would complement the other, perhaps I should put these in the tearoom so that visitors to the garden might enjoy them?

The time for more general seed sowing is fast approaching too. Often gardeners, who generally are an impatient lot, are guilty of sowing seeds too soon. This means that the resultant seedlings will have to be kept hanging around for the next three months or so before the climate is kind enough to plant them in the garden. In turn these seedlings will become weak, etiolated and really rather worthless as garden plants so it is best to wait a while.

However, there are a few seeds that are best sown earlier rather than later, these are the slow developers. Bedding verbenas are one such plant, they are slow to germinate and often the germination too is uneven and thereafter they are slow to make decent plants. The trick here is to order more seed than you think you need so that you get enough seedlings to grow on together of equal size.

Antirrhinums, too, are slow starters that benefit from an early sowing as do begonias but begonias need quite a bit of heat so unless you can provide that I should wait, the resultant flowering of your plants will be later but, so what, they will still flower for you. All members of the dianthus tribe can be sown early too for they have the ability to germinate at quite low temperatures and will make strong, healthy young plants for putting in the garden with little or no trouble.

Another trick to bear in mind when sowing annuals is the timing of when they can be planted in the garden, for some kinds will hold in their pots for a week or so, albeit reluctantly, others will not tolerate being checked in any way, especially by becoming pot-bound, a state from which they never recover. Cleome spinosa is one such plant; well grown it can reach 1.5 metres (five feet) by nearly as much across.

As you will judge from this, you will not need many plants. They come in shades of pink, purplish-mauve and white but the white for some strange reason does not germinate as well as the other two colours - so buy more of the white than you need. Once germinated pot the seedlings individually and keep a close eye on them, potting them on as soon as their roots fill their pots. You should give each plant a single cane tying the leader in as it grows. When planting these giants of the annual world into the garden, I find it a useful trick to make a saucer-shaped dish in the soil around their stems. This helps the water to go where you want it to, straight to the roots.

A well-grown cleome will reach the size of a small shrub in a single season and with their palmate leaves and their spider-shaped flower heads will be a spectacular addition to your garden flowering from July to the first frosts but, beware for they can attract the cabbage white butterfly and their caterpillars and secondly should you need to do any hand weeding among your plants beware, they have some quite vicious spines on the backs of their leaves. Forewarned is forearmed!

•This article was first published on February 7, 2012.