Gareth Carter: Showstoppers for your garden

Magnolia Summer Magic delivers beautiful blooms twice a year. Photo / Supplied

August is a great time to get out and about and walk around our local streets. There are so many signs of spring on its way.

Now is a great time to take a trip to Bason Botanic Gardens on Rapanui Rd which is always a favourite park that I like to visit. The daffodil area is worth a special trip and they are looking stunning at the moment. The neighbouring camellia garden is also in full bloom and worth a walk around while you are there.

Magnolias
Magnolias are a real showstopper around the city at present. If you are looking for a feature tree for your garden, the magnolia is a good one to choose.

There is a range of colours and sizes of plants to choose from including a new 2019 release called Sentry. The blooms are tulip-shaped, have a spicy scent and are a rich pink-purple with white interior.

This tree is hardy and easy to grow. The unique feature is its size - in 10 years you can expect Magnolia Sentry to be around 3.5 metres high and only 1 metre wide. Sentry is the first magnolia which can grow in any small garden as its columnar form takes up so little space. We are excited to have this exceptional new tree in store now -numbers are limited, and once word gets out these trees will quickly disappear.

Another new variety, a 2021 release, is Magnolia Summer Magic. So what's so special about this one? It delivers twice a year with strong, bold pink blooms, flowering in spring and again in summer.

Summer Magic has been bred by Vance Hooper in Taranaki and is described as having elegant, narrow, healthy foliage and is almost willow-like when it's not in flower. These trees have been admired for their foliage alone when not in flower. Magnolia Summer Magic is the best summer flowering magnolia we've seen and can be expected to grow quite slender and tall - the parent tree at 10 years old is 4m tall and 1.8m wide.

Another favourite magnolia that cannot go without mention is Genie. Certainly one out of the bottle, its buds emerge a deep burgundy black, opening to a mass of deep, velvety blooms. It changes through shades of rich purple and red, developing pink edges. Genie will also produce some flowers during summer as well as in August and September. A smaller grower, about 3.5m tall x 2m wide with a tight pyramidal growing habit.

Daphne
Also signalling the end of winter are the sweet smells of daphne and brown boronia.

There are three main varieties of daphne readily available, and most are highly fragrant. These are Daphne Odora Leucanthe, which has a pink flower, and Daphne Odora Alba which is white-flowered. There's also the relative newcomer Daphne Perfume Princess which is pale pink but has a longer flowering time.

Daphne are relatively easy to grow as long as provided with favourable conditions. They prefer a site with morning sun and afternoon shade. Good soil is a must; they are acid-loving plants, like rhododendrons and camellias, and prefer well-drained rich fertile soil.

If you have had difficulties growing daphne, the addition of Yates Hauraki Gold Peat Moss is recommended. It helps improve soil quality in a number of ways, including breaking up heavy clay soils and improving drainage. It also adds body to light soils, retaining extra moisture and nutrients.

Regular feeding with Tui Acid Fertiliser is recommended four times a year (spring, summer, autumn, winter) which generally gives good results if your soil is not very fertile. A top-up dose of magnesium (epsom salts) during May and June, and again in August, will help maintain good health and strength as the plant develops into its final stages of flowering.

Daphne can be grown successfully in a pot. The secret to success is using a good potting mix, such as Ican Premium Potting Mix or Tui Pot Power and positioning the pot in the plant's preferred sun/shade situation. They can be heavy feeders so use a slow-release fertiliser such as Ican Slow Food when growing in pots, with a top up of Burnets Gold Acid Fertiliser every three months.

Boronia
Boronias come in a range of flower colours including pink, red, yellow, purple and brown.

The brown boronia is the most popular and is highly scented. What is intriguing is that a significant number of people cannot smell this magnificent scent. While boronias have a reputation for being difficult to grow, they are worth growing, even if they only last a few years, for the fragrance they offer. The ideal conditions for boronia is dappled light and well-drained soil. However, they do not like their roots drying out, so mulching is highly beneficial.

Boronia megastigma. Photo / Supplied

They are also acid-loving plants so using peat moss, as with the daphne, is beneficial. Feeding boronia should generally be avoided as they have a very low tolerance to phosphate. A light prune after flowering will encourage new growth and prevent the plant from getting woody.

Wind
We are on the cusp of the official start of spring with typically changeable weather. With the changeable weather comes wind. Wind can be quite destructive to both established and new plants.

For established plants, fresh supple growth is easily broken; roses and herbaceous perennials are particularly susceptible. For new plantings of trees, wind can have a long-term effect as the rocking the wind resistance causes on the tree snaps off new feeder roots as they are growing. This can mean a tree never really takes off. Thinking ahead and adding stakes and soft ties now will reduce, or hopefully eliminate, damage.

Brown rot protection on stone fruit
I am noticing the buds just starting to open on my peach tree. In the next two weeks I will need to spray to protect against brown rot that destroys not only peaches but also nectarines, and sometimes apricots and plums, just as they ripen.

The only fix for this is preventative spraying in early spring. Use Yates Fungus Fighter or the new biological organic spray Botry-Zen, spraying once in full bloom and once at shuck fall (when the remains of the flower drop off the developing young fruit – usually one to two weeks following petal fall).

For more gardening information visit www.springvalegardencentre.co.nz

• Gareth Carter is general manager of Springvale Garden Centre.