Be careful what you choose
Christine Walkden, resident gardening expert of The One Show and author of Christine Walkden's No-Nonsense Container Gardening, says you can bag some fantastic bargains, but you need to be aware of what may end up on the compost heap.
"Garden centres are now clearing their shelves of mainstream bedding and herbaceous plants to get ready for bulbs, which generally come in in August, and then for their Christmas stock. If a plant is just reduced because they want to clear the benches, which at this time of year is often the case, you can pick up some real bargains."
As the season began so late this year, there are great bargains to be had, she adds.
Summer annuals at a snip
You can now purchase packs of summer annuals for a fraction of their original cost, as well as ready-made hanging baskets and containers, which if kept fed, watered and dead-headed, should last well into September.
Check plant health
But you need to check the plant's health before you buy, she warns.
"A lot of things are being reduced, but look carefully at what's being offered," she advises. "I would avoid anything soft, squidgy, obviously diseased or weak, the normal poor quality things.
"If the roots of discounted bedding plants are coming through the bottom of the tray, it's probably best to avoid them as they are likely to have been there a long time and may have been starved."
Consider perennials which have finished flowering
Plants which are coming into flower or in full bloom are likely to be more expensive, while perennials and shrubs which have finished flowering may well be among the sale items.
"If perennials have just been chopped back and have a good root system, and the roots are white and fleshy, that's another bargain to be had," says Walkden. You can get all-round interest by going into your local garden centre on the same day every month and bagging a bargain, she adds.
What about bulbs and seed potatoes?
Recently, some centres have been selling off seed potatoes which should have ideally been planted earlier in the year.
Walkden advises: "You can plant seed potatoes until the end of June, while garden centres will be stocking autumn-flowering bulbs now - such as sternbergias and Crocus zonatus - which should be planted by late August.
"Bulbs are interesting because you can plant them totally out of season and they will just flower much later," she says. "If the bulb is sound, with no softness, mould or disease on it and you haven't got round to buying them, then buy them!
"I know lots of people who plant their spring bulbs in December, because they forget, and they'll just flower later."
Consider cheaper varieties
There are other ways to save money on garden centre plants. Some specimens may be more expensive than less popular varieties. Acers, for example, can be extremely pricey, but some argue you can get the same effect with cheaper trees such as cherry or Amelanchier.
Lifting and dividing plants can also be an economical way of increasing your stock and you can do this with many plants, from dainty-looking astrantia, to tropical-looking hostas, heleniums, rudbeckias and crocosmias.
Some clumps of bulbs will separate easily, to give you several healthy clumps to replant, while you may need to get a gardening knife to divide other tougher-rooted types like hostas. But leave this job until the plant is dormant, if you can.