So, you have purchased one or more magnolias (deciduous or evergreen) and need to know how to look after your new treasures. Well, the news is all good, for magnolias are very easy to grow. You would expect such aristocrats to be like racehorses, very temperamental, but not so. They need no particularly special treatment when planted and thereafter.
Except for judicious pruning, and regular fertilizing, they are virtually carefree. Pests and diseases are relatively few (see page 5). The only downside is that they can be expensive to purchase, but I think you would be hard-pressed to find a gardener that regretted the expenditure. Little, if anything, surpasses the exquisite beauty of a magnolia bud, except the flower that follows.
Before planting anything, it is necessary to study the site that you think might suit. First of all, do what I often have not, and that is leave plenty of space for growth. Firstly so you get a specimen, not an amorphous mass, and secondly, if the trees are too closely planted the bottom branches die, which is not pretty. Another reason to be careful in your choice of site is that magnolias, with their spreading root system, do not transplant well, as much of the root system is lost during the move.
Magnolias like sun, so make sure they will get this benefit at least a good part of each day. Only the very large-leafed magnolias, such as Magnolia macrophylla (zones 5-9) need part-shade. Most plants do not like strong winds, so avoid this curse, but other than this magnolias are not particular.
If your garden is sloping you are fortunate indeed, because magnolias may be planted on the slopes so that you look down upon them. I imagine that is how the early plant hunters saw them as they walked along ridges looking into the valleys of magnolia in flower. We can't quite manage such splendor, but in a small way we can replicate this beauty.
Page 1 of 5 – Find out how to go about planting magnolias on page 2.
Magnolias like best to be planted in good, free-draining, preferably acidic (pH 5.0 to 6.5) soil that does not dry out, and they enjoy a sunny situation. However, Magnolia kobus (zones 5-9), M. x loebneri (zones 5-9), M. seiboldii (zones 6-9), M. stellata (zones 5-9) and M. wilsonii (zones 7-9) can grow in moist, alkaline soils and M. delavayi and M. grandiflora (both zones 7-9) will tolerate dry, alkaline soils.
As they like plenty of organic material in the soil, it is sensible to make a very good job of preparing the soil and site. Ensure that you dig a hole much larger than the root ball of the tree and add generous amounts of well-rotted manure and compost to enrich the soil.
If your soil is dry, consider adding water-retaining crystals when you plant. These will expand to hold water when you water the tree after planting and give the roots a prolonged source of moisture to help them get established. It is not that magnolias are so fussy, it's just that you will be rewarded in proportion to the amount of effort you have expended. If you carefully prepare the site, your tree will grow more vigorously and therefore flower sooner. If the soil is poor, then the plant will look stick-like and grow but little a year. Eventually, however, it will flower.
Place your magnolia in the prepared hole, which should be about three times the width of the root ball, being very careful to plant it in the soil at the same level as it was in its container. If the plant has become root-bound in the pot (and magnolia roots tend to girdle, that is, circle the trunk or root ball), gently tease the roots out from the bottom. Be careful doing this, because the roots are quite brittle. You can also cut any circling roots, especially if they are at the top of the root ball or close to the trunk.
Make sure that the tree is firmly in the ground without actually stomping hard on it, and water well. I am a great believer in mulching your plant, being careful, as usual, to keep the material away from the stem to avoid stem rot. This is for more than one reason, the most important being to prevent the plant drying out.
Depending upon what you use as mulch, and you have a wide choice, it can also provide nutrients. Suitable mulches are pea vine or barley straw (you do tend to get a crop of both peas and barley, but that is easily dealt with), bark, mushroom compost, leaf mold or compost.
If your plant is large, do stake it, because wind-rock can inhibit growth badly or kill the plant outright.
Page 2 of 5 – Discover how to prevent frost from harming your plant on page 3.
Having planted your tree, the after-care is not at all difficult. As magnolias are surface-rooting, do not use a fork vigorously or wield a mighty hoe, but do give them something to eat. Slow-release fertilizers are simple and good, and of course compost is wonderful. For the first year, it is necessary to make sure the plant does not dry out, but if you have mulched as suggested, the need for watering will be much reduced.
It is generally accepted that in these days of container plants you can plant them out at any time. This is not a theory to which I subscribe, unless you are the sort of person who will never forget to water when the season is dry.
Fall is a good time to plant, for the soil is still warm enough to stimulate root growth. However, many magnolias are field-grown and therefore would not be lifted until early winter, so the plant you buy in the fall would be a holdover, perhaps getting very pot-bound. For this reason, I feel that spring is the very best option. Having planted, watered and mulched it, your magnolia can then be left to get on with growing without needing further attention for a while.
Coping with frost
If you plant your magnolias with regard to their recommended hardiness zones, they will flower successfully. However, whatever your climate, you may, in some years, experience late frosts, which can damage some flowers. Usually this affects only those species or cultivars that flower relatively early. The climate is unfortunately too variable to accurately predict the arrival of frosts in every year, so if you wish to grow the best of the Asiatic magnolias you are likely to have some years where frost damage will occur.
Having said this, there are some magnolias that shrug off frosts, e.g., Magnolia stellata and varieties and M. x loebneri and varieties, and so are ideal for those who live in areas where late frosts regularly occur, The other option is to choose magnolias that flower later in the season when frost danger is very low, Some suggestions are given in the list below.
Very lateflowering magnolias
M. acuminata, cultivars and hybrids: 'Butterflies', 'Elizabeth', 'Golden Glow', 'Ooldstar','Koban Dori', 'Sundance', 'Yellow Fever'
M. x brooklynensis: 'Daybreak', 'Eva Maria', 'Woodsman', 'Yellow Bird'
M. grandiflora and selections: 'Beauty', 'Bracken's Brown', 'Charles Dickens', 'Edith Bogue', 'Exmouth', Terruginea', 'Goliath', 'Majestic Beauty', 'Russet', 'St Mary'
Page 3 of 5 – Get facts on pruning and fetilizing the magnolia plant on page 4.
There are two schools of thought about pruning: one for pruning, one against – and wouldn't there be. If you are able to plant your magnolia with plenty of space around it, free-standing as it were, nothing looks better than a magnolia with its lower branches intact, so that the tree is clothed from head to foot.
However, life is full of compromise, so what I have found to be most practical is this: if you have to consider space, as most of us do, firstly keep the tree to one stem, where the variety allows. Then when the tree has grown, remove the lower branches up to a height of about 3 ft (1 m) or so.
This allows you to underplant, or should it be a lawn specimen, to mow with your "ride-on" without being beheaded. Pruning will not hurt the tree, but just watch for what are called water shoots (coming from where you cut) and simply remove them.
When it comes to species like Magnolia stellata and its hybrids (zones 5-9), which are naturally very bushy, it might be sacrilegious to suggest that you remove the lower branches so that you have a little tree rather than a shrub. This I have done and think it not only looks well and shapely, but saves lots of space. This is a big help in little gardens.
There are other reasons for pruning. Sometimes trees put up double leaders – that is, two leading or top growths. One will tend to be weaker than the other, so remove it, otherwise when the tree is older, a strong wind could break one leader.
If the tree has branches that cross, they can rub together and cause damage and poor growth, so cut one out. Do this after spring flowering, pruning branches flush with the trunk. Also, be aware that magnolia branches are brittle and can break in ice storms, which is another good reason to prune weaker and damaged branches early.
Magnolias in the wild grow in forested areas with lots of leaf mold for food. As we already mulched when planting, it will only be necessary to apply some slow-release fertilizer each year, in the spring and the fall.
If planted in a field situation, magnolias do not care for uncut grass growing around their trunks, so, if you can, mow around them or spray to prevent grass growth. In the garden, where your tree is probably underplanted, weed control needs to be different. As magnolias have roots very close to the surface, do not hoe, but remove weeds by some more gentle method, such as by hand.
Page 4 of 5 – Discover how to deal with disease and pests on page 5.
Diseases and pests
Magnolias rarely suffer serious damage from diseases and insects. Very young plants can be attacked by slugs, but these pests are easy to control with modern baits. Sometimes, the leaves are attacked by leaf miners that chew through both leaves and flowers. This is especially a problem in the southern United States. Systemic insecticides will control these insects, but they are very toxic and, as the insects rarely kill the host plant, you may choose to live with the problem.
Another insect that might trouble your summerflowering magnolia species and Magnolia grandiflora is the Japanese beetle. These can be picked off by hand, but in big trees and for large populations this is not feasible. If you live in a cold climate, winter will usually kill off these pests for you. Again, an insecticide can be used but you will want to weigh up the damage versus the use of chemicals to control the problem.
Other diseases that attack magnolias are leaf spots, including magnolia scab, and powdery mildew. Where you can reach the problem, spraying with a sulfur compound may help but often control is not needed or not practicable, especially on very large trees where good coverage is not possible. Various cankers, such as nectria canker, dieback and trunk decay can all be dealt with by cutting out the dead or diseased wood. Rarely will any of these diseases cause the death of the plant.
A far more serious problem is magnolia scale (Neolecanium cornuparvitni). The scales are brown, round and about 1/4 in (0.50 cm) in diameter. A white, dusty-looking wax often covers them. Like other scales, they suck sap from the plant and under continuous attack a tree may die. Excess plant sap is excreted as honeydew, on which the fungus sooty mold develops, giving the leaves and branches a telltale black appearance. Check for magnolia scale on any plant you are planning to purchase. If you see them on the plant, don't buy it.
If you find magnolia scale on your trees, you can apply horticultural spray oils (also known as summer oils) at all stages of the insect's life cycle. They kill primarily by smothering the scales and will be more effective if you first remove as many as you can by hand. These oils are most effective if you apply a horticultural oil to settled crawlers (the young of the insect) in late August. Then apply a dormant oil in October to November and again in March. Make sure that the stems and leaves are thoroughly wet.
Contact insecticides can also control scale, but the key to their success is timing. You need to apply sprays when the scale is at the crawler stage – usually late August to early September. (Crawlers are often orange, brown or purple and look like moving specks of dust.) Be sure to read the manufacturer's instructions carefully before using any oil or insecticide.
Other scale insects that attack magnolias include wax scales and tulip tree scales. Treat as for magnolia scale.
Page 5 of 5
Excerpted from Magnolias by Rosemary Barrett and David Bateman. Copyright 2002 by Rosemary Barrett and David Bateman. Excerpted, with permission by Firefly Books. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.