Gareth Carter: Magnolias resplendent despite frosts

Magnolia Sentry. Photo / Supplied

The fine weather with clear skies and four frosts in a row last weekend and early this week has dealt some damage to tropical and frost-sensitive plants in gardens around the city. It shows we can never be too complacent with the weather and it's wise to have some frost cloth on hand for clear-skied nights.

August is a great time to get out and about and drive around the city, enjoying the sights of spring on its way. Bason reserve (on Rapanui Rd) 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.

Despite a few reports from gardeners where open magnolia flowers have been burnt by the frosts, they are overall looking great round the city at present. If you are looking for a show stopping feature tree for your garden the magnolias are a good one to choose. There are a range of colours and sizes of plants to choose from including a new 2019 release called 'Sentry'.

'Sentry' is the first magnolia that we've seen which can grow in any garden as its columnar form takes up so little space. The blooms are tulip shaped, have a spicy scent and are a rich pink-purple with a white interior. This tree is also hardy and easy to grow. The unique feature though is its size - in 10 years you can expect magnolia 'Sentry' to be around 3.5 metres high and only 1 metre wide. We are excited to have this exceptional new tree in store now - though numbers are limited, and once word gets out these trees will quickly disappear.

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 highly fragrant. These are 'daphne odora leucanthe', which has a pink flower and 'daphne odora alba' which is white flowered. Then 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 favoured conditions. Daphnes 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, then the addition of Yates Hauraki Gold Peat Moss is recommended. It helps improve soil quality in a number of ways, including, breaks 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, winter, autumn) generally gives good results. 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.

Magnolia Sentry. Photo / Supplied

Daphne can be grown successfully in a pot. The secret to success is using a good potting mix, such as natural bark brand of potting mix, and positioning the pot in preferred sun/shade situation as discussed earlier. They can be heavy feeders, 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.

Boronias come in a range of colours including pink, red, yellow and purple. The brown boronia, however, 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 trying 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. 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.

Planning Ahead

Bulbs that should be planted now include dahlias, peonies and lilies. These are all summer-flowering beauties that will form increasingly larger clumps each year and provide an increasingly impressive floral display each subsequent year.

Dahlia are well valued for their long-lasting summer and autumn displays. Flowering on plants ranging in size from miniatures growing only 30cm up to large specimens reaching 120cm tall. They are very easy to grow and provide a rewarding display with very little effort. Plant the tubers with the main growing tips just below the surface of the soil. Firm the soil around the tubers, being careful not to damage them. Some taller varieties may need staking and an occasional spray with a fungicide such as Yates Bravo is beneficial to control powdery mildew. To prolong the flowering, pluck off old flowers. This encourages further flowering. Cut back spent foliage to ground level each Autumn. Available in stores now, they can be planted through to the end of the year.

Peonies produce the most spectacular blooms that are a head turner in any garden.

The giant-flowered peonies come in a great range of colours in both doubles and singles. The big, fleshy roots are completely dormant in winter and in early spring emerges rapidly growing stems bearing 1-3 flower buds, these developing slowly to gigantic blooms up to 18cm across. They thrive in cooler districts while a cooler situation is best in a warmer area such as Whanganui. A hint for improving the flowering of these when growing them in a warmer spot is to defrost your freezer and place the ice over them when they are dormant.

Magnolia Sentry. Photo / Supplied

Lilies are very easy to grow and provide a lovely display of colour over the period December to February, depending on the variety. As the clumps of bulbs get larger each year so does the display of flowers. There are tall and dwarf varieties, with the dwarf varieties being particularly great for porches and patios. Taller varieties will benefit from staking in windy spots.

• Gareth Carter is general manager of Springvale Garden Centre.