Magnolias coming into their best
We have experienced a fairly mild August with many days feeling like spring.
There are signs of spring everywhere in our city and district. Many tree buds are swelling, and as the days lengthen more plants come into bloom. Blossom is appearing and green leaves begin to show on the branches of many deciduous trees. Among the most attractive of the early trees are the flowering cherries, plums, peaches and magnolias. Camellias are reaching their flowering peak and many rhododendrons and azaleas are showing their first stunning flowers. Many of our native kowhai trees are about to burst forth in bloom, the early varieties showing off their beautiful golden yellow flowers providing a feast for native birds.
As soil conditions permit, gardeners can look forward to increased activity in the garden. It is a busy time for seed sowing, spraying and fertilising. Buds, shoots, flowers and seeds are sprouting and growth becomes more rapid as daylight hours increase in length. As it becomes warmer, soil temperatures continue to rise. Early spring growth can be difficult with changeable cold snaps, wet weather and frosts possible. Many winter annuals such as primulas and polyanthus are right at their peak now and are making an impressive display.
If you are into seed sowing then now is the time to be sowing trays of summer vegetables and flowering annuals inside or in a greenhouse. These will be ready for planting out in late September or early October to give a well established summer show for Christmas.
Once the flowering of indoor cyclamen has finished, pot grown plants can be transplanted outdoors into the garden in a sheltered location, best under trees where they are well shaded where they will often perform for many years.
Roses are starting their new season’s growth. Regular sprays with Grosafe Freeflo Copper mixed with Enspray 99 Oil will help prevent fungal diseases and insect pests.
Apply a mulch to all bushes along with a dressing of rose fertiliser. Prune hybrid tea and floribunda roses now and feed all roses now as the new growth starts to come away.
It is time to prune all shrubs that flower on new wood produced in the coming spring and summer. Hardy fuchsias and a number of shrubs grown for the colour of their stems in winter such as the red stemmed dogwood, smoke bush and maples can be trimmed for shape.
It is also time to prune hydrangeas, if this has not yet been done, trim down to a fat double bud to ensure you are not cutting off this summer’s flowers. To keep the flowers blue and purple, feed now with aluminium sulphate (aka Tui Hydrangea Blue). For pink and red colours, fertilise with Tui Garden Lime.
It is time to divide up perennial and herbaceous plants, such as hosta and daylily, that have become congested. Replant the outside parts of the plants and throw out the centre portion.
Magnolias are one of the most striking of the early flowering trees and shrubs. We have many quite stunning specimens, coming into flower at the moment, dotted around the city.
The range is extensive containing many varieties of great horticultural merit, including the white star flowered “stellata” types, a great array of tulip flower types and the magnificent evergreen types.
Choose your site for planting a magnolia very carefully, as they resent being moved or transplanted once they are established. Some grow into quite large trees and require ample space to make a great display. Avoid overcrowding them in your garden and do not cultivate ground under them as their fleshy roots are often near the surface and should not be disturbed. Plant them in a full sun position, sheltered from strong winds and where the roots can be kept cool. They enjoy moist rich free draining soils just slightly acid (pH 6.5) with plenty of organic matter added such as peat moss, well rotted animal manure, organic compost or leaf mould. Always plant new trees from the garden centre at the same soil level as they were in their pot and stake securely. Do not tread the root ball firmly as they do not enjoy the soil being compacted.
Mulching routinely insulates the shallow roots from direct sun and helps to retain moisture. Water frequently (without drowning) the roots as necessary while plants are getting established and during dry periods. A top-dressing with an acid fertiliser such as that suitable for camellia, rhododendron and azaleas or sheep pellets after planting and then in the spring once per year will maintain healthy growth. Note that these plants detest lime so never apply it.
Magnolias are rarely affected by pests and diseases with any problems usually due to unsuitable soil conditions or deficiencies. Pruning, if necessary, is best done after flowering only to reduce size and remove damaged branches.
Some of the notable deciduous varieties are as follows:
Magnolia Genie: produces stunning blooms of deep rich purple and red. This tree can suit small and large garden situations alike only growing 3.5m high by 2m wide.
Magnolia Vulcan: produces deep port wine red flowers up to 25cm across. A Felix Jury hybrid that is much sought after and grows 4m x 3m.
Magnolia Stellata Jane Platt: The very best of the pink flowering stellata varieties. Green foliage and gorgeous rich, deep pink flowers in spring, grows 1.5m in 10 years.
New release Magnolia Stellar Gem: this is the latest release from Taranaki breeder Vance Hooper of Magnolia Grove. It was raised as a seedling of Starwars x Genie and flowered years from seed when a little over knee high. (New trees from seeds can often take up to seven or more years to first flower) It truly fits the guideline of a modern garden magnolia in that it is compact, relatively disease free, heavy flowering and produces flowers from the first year. The compact upright habit is reminiscent of the Genie parent, and the purplish pink pointed star flowers are reminiscent of Starwars. Medium sized foliage is also in scale to the size of the plant. There are limited numbers available in store now.
Have a good week.
■ Gareth Carter is general manager of Springvale Garden Centre.