April 2009

Gardening in Canberra

April has brought rain. We are well on track to reach or exceed the monthly average! On the 19th we went to a rare plant fair at Bilpin in the highland behind Richmond (On the road to Mt Tomah). It was a great day for acquiring unusual plants - I purchased the hybrid Brachychitons 'Belladonna' and 'Clarabelle', two Primula auricula and Primula X kewensis, the shrub relative of Camellias - Sinocalycanthus chinensis' and a few other 'wants' including an Hacquetia (Apiaceae).

Last week Urban Services commenced removal of a large gum from our front nature strip. It was leaning dangerously towards the house. This prompted a renovation of the driveway garden and I have planted one of the Brachychitons there, sheltered by a large Cotoneaster.

I potted the Primulas in a mix of sieved peat, sand, potting compost with added seaweed slow release fertiliser, some perlite and a good amount of drainage (crushed bricks) in the base. They are establishing well (picture opposite). In last few days, we have had over 40 mm of rain, and the temperatures are dropping. We expect frost before the end of the week.

Traditionally, Anzac Day is the time to plant tulips in Canberra - as the soil temperatures start to drop. I followed the rule and planted up two hexagonal pots with parrot tulips (Weber's and another one) - refreshing the soil in the pots with store bought bulb soil. The soil in the pots has a high proportion of brick chips and is well drained. In doing the replant I had to relocate the summer dwellers - two types of rosette succulent - to the banksia and driveway gardens. I overplanted the tulips with a perennial snapdragon that had been in one pot for the summer. It was thriving - I think appreciating the loose soil mix amended with water holding crystals. In potting in the tulips I discarded the top part of the soil mix that had most of the water holding crystals as these may not be good for them in winter. Also potted up Tulip 'Queen of the Night' in two squat green glazed pots - adding back a yellow leaved succulent to one side.

Gardening in a warm climate.

The following was first written for Gardening in the Sub-tropics in Your Garden Magazine in 1994.

As we slide into Autumn, the promise of Spring still lies ahead. April is often the main month for planting seedlings for the Spring display, either store-bought or grown from seed planted in early March. As the weather cools, self-sown annuals also emerge. Light waterings every evening ensure that the tiny germlings of poppies survive. Watch for their distinctive pale green leaves and remove other seedlings that may crowd them out.

Mulching is tricky when self-sown seedlings are wanted, a thick mulch will smother weeds and plants alike. I only mulch lightly during autumn, leaving patches of bare soil where small seedlings can grow. Vigourous, heavy seeding plants like Cosmos that grow all year round (in Brisbane) can also interfere with the emergence of the more delicate spring flowers. Cull out all plants from parts where self-sown Spring annuals are hoped for. I help my poppies along by over-sowing with seed from the previous crop that I have saved indoors. Thin emerging seedlings ruthlessly. Move some to other parts of the garden. Once the seedlings are up and away, some mulch can be carefully placed between individual seedlings. Be careful, contact with seedlings, especially in the crown, can encourage grey mould (Botrytis cinerea) and Sclerotinia rot in showery weather. Ultimately, when self-sowing is being encouraged, major mulching is best done at the end of Spring. I lift out the spent annuals, apply a good thick mulch, and reapply the remnants of the annuals (In Canberra, Autumn is the main time to mulch). Seed from the spent plants then lie at the top of the mulch layer, a good position for enhancing survival.

Last Autumn, seedlings of Oriental poppies Papaver orientale were available from local nurseries. These are really perennials, and often don't make sufficient growth to flower in the first season. In our climate, getting the dormant plants through summer, and remembering not to dig-over where they rest is a challenge. Those plants that have survived the summer need to be well fed to encourage abundant growth while it is still warm. The plants grow up to 1 m with large, hairy foliage and produce dessert-plate sized flowers. The plants die down again in early summer, so a late Spring fore-ground planting will ease their passing. It's worth saving seed of any plants that do flower, you may select a strain more tolerant to our climate.

Peony poppies pop up in April, along with Flanders and Shirley poppies (Papaver rhoea). Their smooth, glaucous foliage suggests an affinity for dolomite. The plants appear quite striking even before flowers appear. Peony poppies grow to 1.5m, so early staking will provide support for later flowering. If you have the double-flowered type in your garden, cull any singles that emerge to ensure maximum numbers of doubles next season. In the 1993 season, I had a good number of double white plants, grown fron a single plant that sprang from nowhere the previous year. With dessert-plate sized flowers resembling hemispheres of crumpled white tissues emerging delicately from plump, celadon buds, the flowers are sure to be envied by all who pass. Thin peony poppies to 1 m apart. Grow them in full sun and keep well watered. Avoid overhead watering at flowering, petals on flowers and opening buds can brown, marring the display. Unlike their Oriental cousins, Peony poppies appear to like our climate, they're well worth growing.