growing magnolias

Our bedroom window in Sissinghurst looks east, so during the unbelievable sequence of perfect spring mornings that we have enjoyed day after day and week after week this year, we have looked out first thing to a sun rising behind the trees of the garden.

Several magnolias – all of them miraculously undamaged by either frost or rain – have glowed in that first sun as if full of lighted candles, the branches peering over the garden walls in what is undoubtedly the most beautiful spring that I have ever known.

So often magnolias are full of promise when their buds first emerge, only to be literally browned off by cold weather, but this year they have towered over the garden as the flamboyant climax of spring. Alexis Datta, the head gardener at Sissinghurst who has been here for 20 years, cannot remember the magnolias being so good, the flowers so undamaged.

If they do well, magnolias become more magnificent with every passing year. A really well grown one looks like a huge hot-air balloon of flowers, giving the garden an exciting new dimension.

This spring has made me determined to find out which of the modern cultivars of spring-flowering deciduous magnolias we should be choosing.

Finding the best magnolia varieties

Karan Junker at Junker’s Nursery in Somerset is a great magnolia expert and is in the process of planting a vast arboretum. This will stretch over 20 acres initially and will include 300 magnolia varieties among a planting of more than 1,000 trees.

Magnolias have come a long way in the past decade, with the Americans and New Zealanders the great breeders. The good thing about the new-named hybrids is that they are grown from vegetative propagation – cuttings or grafting – so they flower from an early age, whereas species trees do not bloom until they have reached a substantial size, which can take a lifetime.

The improved forms are bred for large or prolific, reliable flowers, and for a habit of blooming when the trees are still small. Some were already in flower in the pots in the Junker’s Nursery.

It is possible that once planted, they will grow strongly for a season or two and not flower as a result, but they will do so profusely as soon as they are settled in their new positions.

For anyone who has seen Magnolia campbellii in Cornwall, this is the holy grail of the genus, but Karan would not recommend growing it at home. It makes a vast tree that would swallow up the average garden and needs an acid soil.

It also flowers very early — in February — so unless you live in a sheltered site with a well-protected microclimate, you are almost bound to have a frost when they’re in bloom. This will wipe out the flowers in an instant.

According to Karan, this set of climate circumstances only really occurs in some of the great estate gardens in south Devon or Cornwall, and up the west coast where you have Gulf Stream influence, including even coastal south-west Scotland.

Choosing magnolias for your garden

There are so many wonderful deciduous magnolias to choose from for this time of year, so even if you do have a garden big enough, there is no reason to lament Magnolia campbellii. The classic choice for a small town garden is Magnolia stellata. This has widely spaced, spidery petalled flowers and makes a compact plant, shrubbier than most magnolias. Its flowers appear earlier than most, but they are more resistant to frost, so they often look good for most of spring. All magnolias have gorgeous buds – like furry mice sitting on the branches – and these are easily seen on any of the stellata forms.

Karan takes me off to look at a very beautiful pale pink-to-white stellata, 'Jane Platt’. It has all the reliable features of stellata, but its unusual, subtle colouring makes a good change from the pure white that one can almost tire of seeing in suburban gardens.

Most magnolias will grow happily in shade, but many won’t flower well. However stellatas are brilliant in woodland gardens because they flower profusely even in shade. As Karan says, this one is crying out to be put in a vase by your bed. If you’re going to do this, sear the stem end in boiling water for 30 seconds to make it last as long as possible.

Centre of attraction

My number one favourite at Junker’s is 'Apollo’. The flowers are glamorous with a distinctive two-tone effect. They are a dark pink when they open, but fade to a pale pink or white as they age, and this is a beautiful mix.

The scent is not powerful but incensey, rather like a lily. The anthers are a dusky pink, with a deep pink filament and they have a very exotic-looking stigma with a green centre, covered in lots of pink hairs.

This is particularly noticeable in this cultivar because the petals reflex at maturity, which really shows off the centre. 'Apollo’ is a shrubby variety that most of us could fit in our gardens, and Karan advises that overall it is an excellent, easy plant.

'Ian’s Red’ is the next one I pick out. This comes from New Zealand and has campbellii genes in its mix, giving it huge and impressive flowers. They have a slightly textured surface – like raw silk curtains; they are the colour of blackcurrant mousse and smell deliciously of apples.

Another of my favourites is 'Alex’. This is also fragrant — smelling of lilac – and has perfect tulip flowers, pale pink on the inside, with magenta-crimson pigment softly dusted on the outside. It has a lovely bronze tinge to its just-emerging leaves.

'Joli Pom-Pom’ is also irresistible, with pure white flowers that look like glorified water lilies.

The flowers have an wonderful texture and there’s a huge clutch of striped anthers, green and pink with a purple top and elongated bright green stigma. These look like a zinnia slotted in the middle of the flower.

Another lovely white with a smaller flower size is 'Pirouette’.

These remind me of gardenias, fully double with lots of petals. Karan loves this one – an instant button hole. It can be pure white or have some pink in the flowers, depending on the weather. It has a good scent, sweet but slightly camphory.

For anyone who wants a medium-sized tree, Karan recommends 'Red Lion’. This has huge flowers in the classic magnolia tulip shape, pink with the outer petals dusted and feathered deep-pink on cream. Some of the flowers are much darker with no hint of cream.

The flower stems comes straight out from the branches, holding all the tulips very upright. Ladybirds love over wintering in the buds.

The final magnolia that we look at is 'Goldfinch’. As well as white and pink, magnolias also come in yellow forms. These are the latest to flower, coming into bloom from late April through into May, so with any luck they will be safe from frost even in colder areas.

'Goldfinch’ is one of the earliest of these yellow varieties, and it is derived from the North American species Magnolia acuminata. These thrive even on alkaline soils, and grow well on chalk.

Late spring is an ideal time for planting. What you do now will shape your garden for decades, or even centuries, to come.

Magnolia planting and growing tips

Magnolias are cold hardy and resilient. Foliage blackened by a late frost will soon sprout again.

Karan strongly recommends investing in larger plants. At Junker’s they find that magnolias establish much more reliably from a larger plant.

Magnolias have traditionally been considered to have a preference for acid soil, but Karan has concluded that the structure of the soil is more important than the pH.

Magnolias hate to dry out in the summer. Their huge leaves need plenty of moisture. This condition alone will damage them more than anything else. So add a little organic matter as you backfill the planting hole.

Leaf mould or garden or municipal waste compost is the stuff to use, not mushroom compost. The key is then to mulch very generously on top and to do so again in the spring every year.

Junker’s Nursery Ltd (01823 480774; www.junker.co.uk). Visitors are by appointment only please.