I am a great one for telling people that 'size isn't everything' but, looking through the various plant catalogues that regularly hit the door mat, it would appear that I am wrong for most of them seem to contain giant this, the biggest that and the tallest ever, how things have changed!

Years ago, dahlias were frowned upon by the gardening cognoscenti as being common; they were confined to allotments and cottagers' vegetable gardens, today the reverse is true. This is largely thanks to the first of the dark-leaved varieties, Bishop of Llandaff being grown in the red borders at the National Trust garden at Hidcote in Gloucestershire.

Gradually other varieties of dahlia achieved a level of respectability as gardeners began to use colour once more and appreciate their true worth as garden worthy plants, for during the 1970s, everyone wanted pale and interesting colours in their gardens.

Thank goodness for changes such as these, for we would miss so much if we only used a pallid, pale palette in our pleasure gardens. So it is that Dahlia Bishop of Llandaff has given way to a whole series of Bishops, all with dark glamorous foliage but, with flowers in almost every shade that you can think of.

Today we have plant catalogues that list a new dahlia called 'XXXL' with blooms up to 30 cms (12 inches) across, dear readers, how vulgar is that? That said, I bet that there will be lots of you trying these super-sized varieties! However, do bear in mind that these gargantuan blossoms weigh a ton and will not stand well in windy conditions, especially when wet but they do have a certain impact.

We grow a very large flowered one called Caf� au Lait which has creamy-pink, cactus type flowers and attracts lots of attention from garden visitors, even those who think that they have impeccable taste cannot help, albeit grudgingly, bestowing it the odd admiring glance. A single blossom displayed in a large goldfish bowl always looks stunning especially if we add some green glass pebbles for it to sit on.

To successfully grow such giants, and they are fun to have, first you will need to manure your garden very well for these plants are gross feeders, then you must equip yourselves with some stout wooden stakes, these will need to be one third taller than the ultimate height of the plant that you are growing and preferably be pressure treated against rotting.

Next you will need some good quality garden twine, I like three-ply fillis or you can try some of the new soft rubber stretchy ties that are sold in several different strengths. Tying your plants in on a regular basis is essential for it is easy to get caught out by a sudden squally rainstorm which could put a sudden end to your efforts. Dead-heading is also essential for once a dahlia has set seed its flowering power will become diminished. If you decide to have a go, I wish you luck.

Fuchsias with very large flowers have also become fashionable but, again, these will test your skill as a grower for sometimes their blossoms are so heavy that their weight can cause the stems to fracture spoiling the display. Also they are not really suitable for growing outside as these large and luscious blossoms are easily bruised and battered by strong winds and on our island we have plenty of these.

However, they are fun to grow under glass where they can be properly supported; it would be nice to grow them as a traditional pyramid where a strong framework of old branches is retained rather like growing a standard. Some of the heads on our standard fuchsias had become overly large and quite out of proportion with the length of their stems so this autumn I cut several of them back into old wood, what's known as a jolly good haircut!

I have been holding my breath all winter in case I had gone too far rendering them unable to make new shoots from mature wood but, at last they are beginning to break. Now I need not live in fear that their too large heads might get snapped off during windy weather in summer.

I do not see any charm at all in giant flowered hibiscus with blooms up to 30 cms (12 inches) across, in pictures advertising them they are always in perfect condition but, the reality is that this lasts but a day if you are lucky. Their other downfall is that there are rarely more than one or two blooms open at any one time so although an individual bloom might make you gasp with either joy or horror, depending on how you view it, the plant itself is most unlikely to thrill you. That is just my humble opinion, I'm sure that someone out there will prove me wrong!

Another very large growing plant that might tempt you are some of the Goliath lilies, these can, in their second year run up to heights of 2.5 metres (8 feet) tall, each flowering stem producing as many as forty very large, heavily scented blooms each up to 20 cms (8 inches) in diameter. These are fun but, again they do require a certain amount of work on behalf of the gardener.

Staking is of paramount importance to support these large heavy heads and the stakes must go right to the tops of the flower clusters too otherwise there is a danger that these will snap off or break however, should this happen all is not lost for they make rather lovely cut flowers. These lilies also make great pot plants for popping into gaps in your borders or grouping beside doorways, garden gates and on steps, anywhere where you will pass them frequently so that their rich scent can assault your olfactory senses. Although size really isn't everything, it does have its upside and the above plants prove that big can be beautiful too!