Gareth Carter: The tough get growing

This past summer has been a complete contrast to the last one, and autumn to date continues with very summer like weather!

The warm weather and reasonable moisture in the later part of summer has made for some rapid plant growth in many gardens.

The flowering of Silk trees (Albizzia julibrissin) this year has been spectacular as the high temperatures this season was a boon for plants such as these, producing not only a much larger quantity of flowers, but also the length of the flowering season was longer.

Originating from hot dry climates of Australia and Africa this season has provided the silk trees with heat they are natural to.

Also originating from hot, dry climates is the Bougainvillea. These too I have noted have had good flowering with the high sunshine hours and warmer temperatures.

Varying seasons from year to year is a test of the resilience of a garden with some faring better than others each year under the varying conditions.

There are a number of plant species that not only survive on summer weather but that actually thrive and revel in the warmer, drier months of the year.

NZ Natives

There are a few NZ native trees and shrubs that thrive in dry conditions. The pohutukawas are certainly one of the most popular, with the dwarf variety 'Tahiti' (which only grows 1m by 1m) that has brilliant orange-red flowers during summer and into the autumn. It makes an excellent plant in the garden or in pots. Coprosmas have many species that excel in dry, hot conditions.

They also attract the birds with the berries that develop each year. The range of varieties is diverse with a number of colourfully leaved shrubs growing about 1m-1.5m high, as well as several groundcover varieties. The ground cover Coprosma Hawera and Taiko varieties are excellent for covering banks or other areas in the garden where conditions are tough and a dense ground cover is required.

Grass species such as the mini toe toe and the brilliant orange foliaged Carex testacea provide excellent landscaping opportunities when used in groups of three, or in larger mass plantings, using the colours of the grasses to contrast against one another. Many varieties of Lomandra are also top performers in these conditions.

There are some varieties of Pseudopanax which also thrive in dry, summer conditions. Pseudopanax have unusual and decorative leaves and are indispensible plants in garden plantings. They are generally hardy and grow freely in sun or shade and will grow under adverse conditions. The lancewood (Pseudopanax crassifolius) is a distinctive and extraordinary looking plant with a single erect very flexible stem from which long leathery leaves hang out at odd angles. It is a dramatic plant which undergoes many changes throughout its life. A very popular variety is 'Cyril Watson'. It is prized for its lush tropical look, it has a bushy compact growing habit with thick leathery leaves. This plant is adaptable to many conditions and thrives in dry sunny situations once established.

Tough Shrubs

One of the best performing small growing plants for dry areas is the 'Morning Glory' Convolvulus cneorum, not to be confused with the problem weed of the same name! This plant is not invasive, it is a plant that offers almost year round colour, it is seldom without a flower. White trumpet flowers are 3-4cm across with bluish tingle, shaded yellow in the throat. It grows 60cm high by 1m wide, the foliage is a stunning silvery-grey.

Bottlebrush (Callistemon) is another plant that thrives in dry, sunny areas of the garden. There are a number of varieties around, though there are two most commonly available and good for Whanganui gardens. Callistemon 'Red Clusters' has stunning bright red flower spikes that cover the plant in abundance during spring and summer, though it usually has a few flowers on it throughout the year. This variety grows approximately 3m high.

Callistemon 'Little John' is a compact dwarf growing bottlebrush. It only grows around 1m x 1m so is suitable for smaller gardens and shrub plantings. It is often used in traffic islands and other public areas where growing conditions are tough.

It produces masses of deep red flower brushes tipped gold mainly through spring and early summer with occasional blooms almost year round.

Gareth Carter is General Manager of Springvale Garden Centre
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