Garden by the weather this month as autumn slowly approaches!

While it may be warm to hot during the day, there’s a hint of autumn in the air. Days will be getting shorter and nights a little cooler which adds to the change of the season. Some deciduous plants start to colour this month, and autumn-flowering shrubs begin to bloom but there’s still plenty to harvest in the vegetable patch. Make the most of March to enjoy the garden while conditions are warm and to plan for the months and seasons ahead.

Getting that autumn feel with a colourful foliage plant

Deciduous trees, shrubs and vines bring colour to temperate climate gardens during autumn and early winter. If your garden lacks deciduous autumn colour, March is a good month to visit your local hardware or garden centre to select plants which colour up in autumn. Colourful varieties include Japanese maples, ornamental grapevine and ginkgo.

When selecting a plant, especially a tree, read the plant tag. It will have its growing requirement, including height and width. Always ensure you have the space to accommodate the plant. If unsure of your selection, talk to the horticultural staff who can advise you on your plant choice.

When preparing for planting, soil preparation is the key. Start by removing weeds and unwanted plants. Add homemade compost and organic matter and/or Seasol Super Compost to the soil. It has everything in the bag to take the guesswork out of improving the soil.

What to do in your garden in March 2023
How to look after young bulbs

Bulb planting starts now

March is also the beginning of spring bulb planting time. Bulbs such as daffodils, tulips, hyacinths, anemone, ranunculus and Dutch iris are planted in autumn to bloom from August to October. Bulbs can be ordered online from specialist suppliers or bought from local garden centres and hardware stores.

To make an impact with bulbs, mass plant them either in garden beds or in containers. If soil and climate are right, bulbs are a good investment as they’ll naturalise, multiply and reflower year after year. Most bulbs like well-drained enriched soil in a position that’s sunny through winter. Start ordering or buying bulbs now ready for planting as soils cool.

When planting bulbs follow the directions on the pack and mix Seasol Plant + Soil Booster into the soil. For more great advice, check out our spring bulb guide.

Sweet peas

Sweet peas (Lathyrus odoratus) are one of the most rewarding flowering annuals to grow through winter. They have masses of sweet-smelling ruffled, pea-shaped blooms that bring charm to any garden. They also add colour when other plants are dormant, and a trellis of sweet peas can be used as a living screen.

They come in many pretty colours including pink, tones of purple, red, white and bicolours and they are all fragrant. For a continual display of flowers liquid feed them every fortnight with PowerFeed PRO SERIES for Roses & Flowers and regularly pick a bunch of blooms in the early morning for a spectacular vase display. This way plants can put more energy into blooms instead of going to seed.

Sweet peas are easy to grow as long as you give them full sun and protection away from strong winds. There are a few pests such as aphids, mites, snails and slugs that love to eat their juicy foliage so keep an eye out for them.

Tips and ideas for planting a beautiful sweet peas
Tips and ideas for planting a beautiful sweet peas

When to plant sweet peas

Sweet peas seeds are sown in autumn and spring for flowers from winter to summer (depending on the variety and climate). Sweet pea seedlings are also available from hardware and garden centres.

They grow best in full sun in slightly alkaline soil enriched with well-rotted manure and compost. Sweet peas climb to 1.8m high and need a tall, sturdy trellis or tripod to support their growth. They use tendrils to climb and often need to be helped to reach the bottom of their support system with the aid of twigs.

The traditional planting time for sweet peas seeds in Australia is St Patrick’s Day (March 17) but where conditions are still too warm for successful sowing, use the traditional date as a reminder to buy seeds and start preparing for planting when air and soil temperatures begin to cool later in autumn. In cool zones, sweet peas can also be sown in late winter or early spring for summer flowers.

Five important jobs for early autumn

  • Feed and rejuvenate the lawn with Seasol for Lush Green Lawns hose-on after summer stresses. It helps to promote healthy, strong, green growth during autumn. Safe on all lawns, however, if you are after a Buffalo-specific food, try Seasol for Buffalo Lawns.
  • Continue deadheading summer-flowering plants, particularly roses, dahlias, agapanthus and petunias.
  • Keep watering if the days are warm. Pay particular attention to plants in containers and under the eaves where rain doesn’t reach them.
  • Don’t forget the Seasol. Regularly apply  Seasol every two weeks throughout the season, especially for new plantings and frost-sensitive plants.
  • Prune geraniums and pelargoniums and use some of the prunings as cuttings to grow more plants to brighten your garden next spring and summer or to give as gifts.

Pumpkin checkup

By autumn, pumpkin vines have sprawled across the ground and should have formed a good crop. Pumpkins are ripening now but don’t pick them too early, as they will not store well if they haven’t fully matured. Wait until the vine starts to die back and the stalk starts to shrivel before cutting them with a little stalk attached.

To allow the vine to concentrate on ripening what’s there, remove immature fruit. Keep plants well-watered if days are hot. If the weather and soil are wet, slip a flat tile under the pumpkin to keep the skin out of direct contact with the soil. This reduces the chance of the pumpkin beginning to rot. In areas that get frost, the first frosts will kill off the pumpkin vine and reveal the crop.

For great tips on growing and harvesting pumpkins, check out our pumpkin guide.

Seven handy tips on how to grow versatile, tasty pumpkins

Powdery mildew on vegies

Expect to see powdery mildew attacking summer vegies that are coming to the end of their life. Particularly vulnerable are zucchini and squash, which can develop mildew on their leaves, which then brown and die.

Don’t reach for the spray as it’s a food crop however, just remove the worst affected leaves and, as the harvest finishes, remove the plants. You may notice a yellow and black spotted ladybird on mildew-affected plants. This ladybird is feeding on mildew!

After you remove your plants, replenish the soil with Seasol Biochar with Zeolite. It brings it back to life with a dynamic mix of all natural Biochar, Seasol, Zeolite and Paramagnetic rock (rock minerals) to help promote microbial activity, water and nutrient retention. Let the soil rest for a couple of weeks before planting your autumn crop.