Gardening: Hot pots for summer

Your garden can be a bit like your house interior. Once you have your structure in place, it's quite easy to change a few elements for a refreshing new look. Pot plants are in the cushion, vase or throw category - they are simple to set up, relatively cheap, and the sky is the limit for colour and style. Decide if your plant is to be permanent or a seasonal piece. Sometimes you can combine both, by choosing a perennial central element, and underplanting with annuals.

Mediterranean plants like the heat and look gorgeous in Italian-inspired terracotta. Because terracotta is porous, it pays to paint the inside of the pot with a sealer. This reduces watering. If you like the aged look, whitewash the pot with lime slurry, or paint with diluted, naturally pigmented biopaint. Test pots can be bought from biopaints.co.nz. Or, paint with yoghurt and leave in a damp shady spot (best done in winter) for moss or lichen to grow.

Try Mediterranean purple-flowering herbs such as rosemary, small lavenders, thyme, green or yellow-leaf oregano, or silver or purple sage. Garlic chives are hardy and also have cute purple flowers. Pelargonium is a classic potted standby; its foliage and flowers contribute an uplifting scent in a sunny spot.

It is time to repot houseplants that look under the weather or have outgrown their station. Ensure slow release fertiliser is in your potting mix. Remove dead leaves, check for scale or mealy bug and wipe off or spray with neem oil. Rinse dust off leaves.

If an outdoor pot plant looks tired and you suspect it is pot-bound, carefully excavate the plant. A serrated knife down the side helps. Gently prise open and trim overgrown roots. You may need to trim back the main plant, then repot in fresh potting mix to reinvigorate, or put in a slightly larger pot. If that's too much hard work, scrape back the loose material in the top of the pot, without damaging the roots, and apply home-made compost, rock dust or sheep pellets. Water well, then mulch.

Remember, individual pots are little islands, so group together for easy watering. This also reduces the surface area exposed to drying sun and wind. Adding water-retaining crystals to potting mix is a good idea over summer, and keep the surface mulched with pebbles to reduce water evaporation.

In some cases, hooking pots to a timed drip irrigation system is the way to go, particularly if you'll be away over summer. Self-watering pots are also good options. Regularly nip out shoots of sprawling plants to keep them bushy, and regularly deadhead flowers to encourage repeat flowering for a summer of colour.

MIX IT UP

Pick up a few cheap annuals or seed packets at the garden centre and play with your own colour themes. Mix up plants that grow to different heights, just as you would a garden border. Your base could be a groundcover plant that will drape over the sides of your pot. Alternatively, spice up existing permanent pot plants with annual underplanting, or combine with divisions of perennials.

Here are some suggestions for themed plant combinations. The first plant mentioned in each combination would be the focal point of the pot; the second is a type of bushy filler and the last is a draper groundcover. (P) means perennial.

Sophisticated riches:
* Euphorbia 'Tui' (P), Petunia 'Black Velvet', golden oregano 'Aureum' (P)

* Double red begonia (P), Salvia 'Blue bedder', variegated liriope (P), Dichondra 'Silver Falls' (P)

* Astelia 'Silver Spear'(P) and blackish purple Aeonium arboretum 'Zwartkop'(P) (both prefer dry conditions)

Hot and exotic:
* Petunia 'Pretty Much Picasso', lime and pink zinnias, basil 'Dark Opal', Alyssum 'Pastel Carpet' mixed

* Miniature chilli pepper 'Basket of Fire', lime Nicotiana, orange Nemesia 'Kumquat'

* Tub/large pot: hibiscus (P), underplanted with native groundcover Fuchsia procumbens (P)

Kitchen inspiration:
* Dwarf cherry tomato 'Red Robin', sweet basil, lettuce 'Little Gem', variegated lemon thyme (P)

* Coloured veges: Coloured ornamental kale or 'Rainbow' chard

* Large pot: globe artichoke (P), top-flowering nasturtium 'Black Velvet', strawberries (P), thyme (P)

Cottage colours:
* Blue cornflower, Lady's Mantle (P), white miniature Chrysanthemum 'Snowland', blue lobelia.

* White bearded iris (P), Nepeta (catmint) (P), Scabiosa
* English lavender Lavendula angustifolia (P) or stoechas (P) by itself. Mulch with limestone chips or white shell

* Tub: Compact hydrangea such as Hydrangea 'Bodensee' (P) (not for all-day full sun)