With extreme care, purple bougainvillea will cover a tree and look stunning right through the hot weather. With no care and a frost-free climate, you may end up with a house and garden looking like Sleeping Beauty's palace, all thorns and no Prince to hack it back. In warmer climates, stick to dwarf bougainvilleas, preferably in pots on a patio.

But here, where we can go down to minus 9C, I managed to have one by cosseting a cutting for three years in a pot, planted it in late spring by a pittosporum, and now, a decade later, the tree is a great mound of purple even in the driest years. N.B. The tree can also be mown around, just in case the bougainvillea decides to invade the Sudetenland, or at least the Southern Tablelands.

Purple sage is another glory, keeping its flowers from mid-summer to the first bad frost of the season time. I've admired Japanese barberry (Berberis thunbergii) in friends' gardens, but never tried them, mostly because you can't eat them most of our garden is edible or can be used in some way by the wombats, wallabies and other local inhabitants. Purple-leafed flaxes (Phormium spp) are okay, and certainly hardy, but although we have a couple I'm not tempted to put in more. The native purple hop bush (Dodonaea viscosa purpurea) is hardy and a stunner in vases. (Note to myself: buy another as ours is now too tall to easily harvest.)

The most darling of our ornamental purples is a purple-leafed varieties of smoke bush, though I have never been able to find one quite as deeply purple and, yes, must get around to taking cuttings, as I have promised myself for the past 10 years but not got around to. Be warned: some so-called purple smoke bushes are more green than red or purple. Make sure you buy a named variety known for good leaf colour (such as Cotinus coggyria purpureus 'Velvet Cloak', 'Grace' or 'Royal Purple') and even then, if possible, look at the plant before you buy to make sure it is a true deep purple.

We also have a purple/red leafed plum, so beloved of the older areas of Canberra, but make sure you choose a variety that fruits too some are simply ornamental. On the other hand, if you don't want to make plum jam or give away a basket full every few days, do get one that won't fruit and attract fruit flies. There are some wonderful purple-leafed crabapples that fruit well as well as looking marvellous. One of ours, a Tasmanian seedling, has crabs the size of a baby's fist, with red skin and purple flesh, and makes a stunning crabapple jelly.

BLUE BY ME

I'm not sure if blueberries really count as purple. They're not called "blue" for nothing, plus the leaves are green, green, green. Blueberries also need water, often and without fail, or they will die on you, as nearly all mine have. Blueberries were originally a wild crop, growing in cold swamps in northern America and Europe, which gives you an idea of their preferences. But blueberry fruit will also rot in too much rain, and their roots will rot in stagnant water. Think damp, but well drained and fertile and mulched, mulched, mulched.

Until the last couple of decades you could only grow good blueberries in cold climates. Now there are berry varieties for as far north as Brisbane, and even further north, from the southern high bush varieties that were bred in the southern US and are good for home gardens but still need winter chilling, to the rabbit's eye varieties bred for the subtropics, with smaller fruit that are supposed to look like rabbit's eyes, though not like any rabbit I've ever seen.

Choose varieties carefully. There are many on the market, some needing intense cold for the fruit to set, others better suited to temperate areas. Varieties such as 'Brightwell', 'Gulfcoast' and 'Backyard Blue' are good for the subtropics. So is 'Sharp Blue', but it can become soft quickly in hot wet weather.

'Blue Rose' is best for cooler climates, where you wear not just a jumper but a thick woolly scarf for most of winter. There are also small growing blueberry bushes, to about one metre, such as 'Sunshine Blue', as well as bushes that fruit as early as December, or ones that crop almost constantly from December to March.

In other words: check the label, Mabel, and find out exactly what conditions that blueberry bush in the nursery likes. Some need cross-pollination too two varieties that will pollinate each other. Other varieties, especially those bred for colder climates self pollinate, and you'll get fruit from only one bush. Some grow one metre high, others grow up to three metres high and wide.

Blueberries need full sun, though if you are growing them in a harsh hot climate or a patio that resembles the Sahara Desert, find a spot where they'll have morning sun but afternoon shade. If you are growing them in a pot make it as big a pot as you can and, again, keep up the water, using water retaining crystals and a good rich water retaining potting mix, and repot every year or two, as the soil in pots can turn into something like concrete fast, repelling water rather than letting it soak into the roots. They also need slightly acidic soil, so don't lime them, and make sure there is lots of organic matter.

Mulch your blueberry bushes twice a year, whether they are in pots or not. Scatter good organic fertiliser in late winter and after the fruit has set. You should also give them rock phosphate the first year, and then every three years afterwards, but check the label on your fertiliser if it's rich in phosphorous you won't need to give them extra. Blueberries also need trace elements such as copper, iron and magnesium, but a good rich mulch like lucerne may supply these as it breaks down.

Out in the garden, space the plants between one and three metres apart, depending on how big the label says your bush will grow though commercial bushes are planted closer and thinned later. Plant them when they're dormant, or in pots at any time of the year.

Prune the young plants heavily to encourage bushy growth: cut away any weak growth, any frosted branches and any dense, low growth. Also, cut out old wood (more than three years old) every year. It's also a good idea to spray with Bordeaux copper sulphate spray in mid-winter, or in mid-winter and at bud burst when the flowers are almost but not quite open, to control fungal disease in moist areas or wet years.

Blueberries will give some fruit when they are between two and six years old, but bigger, more mature bushes of course produce much more fruit. A big bush yields from two to 10 kilograms of fruit. An avid blueberry eater, like me, needs about three large bushes to have all the blueberries they want, plus at least one or two more for fruit for friends.

Let the fruit ripen on the bush: it won't become sweeter after it has been picked. Don't pick for a few days after they become blue, for the richest, sweetest, sun-ripened flavour. The best way to tell when your crop is ready to pick is to taste often, which is not a hardship. Pick the fruit at least once a week. You'll find that the fruit in the clusters probably won't ripen evenly, so you'll need to selectively pick rather than cut the clusters off.

And you will then discover that a home-grown blueberry is as stunningly richer in flavour as any other fruit or vegetable. They may be actually not be purple, but they taste purple, totally lustfully luscious.

This week I'm:

Sweet potato and blueberry cake

1 cup mashed sweet potato

125g butter

1 cup brown sugar

2 eggs

2 tsp vanilla paste

1 cup fresh or frozen blueberries (don't thaw if frozen)

2 cups self-raising flour

cup cream

Line a large tin with two layers of baking paper. Cream butter and sugar; add eggs one by one; then sweet potato, vanilla, fruit, then the flour and cream. The mixture should be quite moist, but if is seems too dry (which it may be if the sweet potato is dryish) then add a little more cream. Pour the mix into the tin; bake at 200C for one hour or till brown on top and a skewer comes out clean. This cake is rich, moist and very, very good.

Date and almond zucchini slice

125g butter

1 cup brown sugar

2 eggs

1 tsp vanilla

1 cups self raising flour

1 tsp mixed spice

2 cups chopped dates

cup almond meal

2 cups grated raw zucchini

Cream butter and sugar; add eggs; mix in other ingredients. Spread into greased and floured tray; bake at 200C for 30-40 minutes. Test with a skewer. Cool a little before turning out of the tray. Cut into slices with a sharp knife while still warm, but out of the container, to help prevent crumbling.