Alta Southern MagnoliaMagnolia grandiflora 'TMGH' (PP#11,612)
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Magnolia grandiflora 'TMGH' (PP#11,612)
Outdoor Growing zone
The Alta™ Southern Magnolia is the perfect choice for limited spaces and smaller gardens, because it has full-sized blossoms on a narrow, columnar tree that is never more than 10 feet wide. The leaves are large, but narrow, keeping the tree neat and in proportion. The 10-inch blossoms spread their broad petals in spring, and bloom for more than two months, releasing a delicious, rich fragrance. This tree is perfect for a lawn specimen in a smaller garden, or for planting against brick walls between windows. In colder areas it can be grown spread out on a sunny wall. It also makes the perfect narrow evergreen screen or informal hedge.
Always plant the Alta™ Southern Magnolia in full sun, for the best growth. It grows best on deep, moist but well-drained, acidic soil, but with plenty of organic material added to the soil, and a good fertilizer program, it can be adapted to any well-drained soil. Established trees are moderately drought tolerant, but too much dryness will cause leaf yellowing and reduce flowering. This variety has an unusually fibrous root system, which makes planting easier and reduces the risk of transplant shock.
Evergreen magnolias are star performers in the garden, with their magnificent foliage and enormous, scented white flowers. Sadly, this tree in its natural form is too big for many gardens, and it is usually only hardy to zone 7. What is needed is a tree that is narrow, so that it fits into smaller spaces, and that survives in colder areas. Thankfully there is an answer to this need – the Alta™ Southern Magnolia. This tree grows to 20 feet or more, but it stays well below 10 feet wide, fitting into smaller spaces, such as between windows, or in narrower beds. It is also reliably hardy throughout zone 6, and even in sheltered parts of zone 5, making it possible for a whole new group of gardeners to experience the joy of growing a southern magnolia in their gardens.
The Alta Southern Magnolia grows into a narrow, upright tree, a little more than twice as tall as it is wide. This is very different from the original southern magnolia, which is very wide-spreading, and that can be wider than it is tall. Within ten years your tree will be approaching, or even exceeding, 20 feet tall, but be only 8 to 10 feet wide. The branching is very dense, and it readily forms a solid tree, making it useful for screening. The leaves are large, 6 to 8 inches long, but narrower than in other forms of this tree, just 1½ to 2½ inches wide. This give the tree a distinctive, neater character. The upper surface of the leaves is a lustrous, glossy deep green, and the lower surface is covered in a dense rusty-brown ‘fur’, called pubescence. Even if this tree didn’t flower, it would be grown just for the beauty of its foliage.
Plant the Alta Southern Magnolia as a specimen tree on a lawn, or around your home. Planted between windows it is a beautiful way to cover a blank wall and add height without a lot of width to your foundation planting. It is a great choice for the back of large beds, or for the sunny edges of a woodland. It also makes a great screen or informal hedge. Planted at 5-foot intervals it will give solid cover in 5 years or so. Do not plant less than 4 feet apart, as the roots need room to develop. Pruning is not needed to maintain a narrow profile on a screen, as this tree is naturally narrow and upright.
You do need a little patience to see your Alta Southern Magnolia flower, but it will be very worth it. Young trees normally take 5 to 8 years to flower, but when they do it is spectacular. This variety has full-sized flowers, 8 to 10 inches across, with eight thick lush creamy-white petals that open out almost flat, creating the classic ‘dinner-plate’ look of this tree. Flowering is in spring, in mid-April in warmer zones, and a little later in cooler ones. The flowers have a delicious rich fragrance that wafts across your garden, conjuring up images of ‘Gone with the Wind’. Each individual flower lasts around 10 days, and since they open in succession, blooming continues for 2 months or more. Older trees may produce more buds in summer, depending on the climate and growing conditions. Flowers are followed by unusual-looking seed pods, that look a little like pine-cones. These are rusty-brown in color, and in late summer or fall they ripen, releasing surprising large, bright red seeds, which hang from a mucous thread for a time before dropping to the ground.
There is a more technical feature to this variety too. Southern magnolia trees are known to be difficult to transplant, and they often have coarse, long roots that are easily damaged. The Alta Southern Magnolia is notable for its very fibrous, dense root system that makes it easy to plant, and that reduces the risks of transplant shock and other problems – another good reason to choose this variety over other ones.
Plant the Alta Southern Magnolia in a sunny place. The further north you are, the more important full sun is. This tree is completely hardy in zones 7 to 10. In zone 6 plant in a spot protected from cold winter winds, with winter sunshine all day long. This tree can even be grown in warmer parts of zone 5, in sheltered gardens, preferably up against a south-facing wall. The corner between two walls of your home is ideal in a cooler zones, or grow it as an espalier, spreading the branches out across the wall, for a beautiful garden feature. The soil must be well-drained, and moist, rich soil is ideal. Soil that is slightly acidic is beneficial or use chelated iron supplements in spring on alkaline soils. Good soil over a clay base is acceptable, and the clay is a good source of nutrients, as this tree is a heavy feeder, especially when young. Use a balanced fertilizer blended for broadleaf evergreen trees. Rich organic mulches over the root zone in spring are a good way to both conserve moisture and provide a broad range of nutrients to your tree. Watering during dry spells in summer, especially in the early years, is valuable too. If the leaves begin to look pale green, you probably need to water more, apply more fertilizer, or both.
The Alta Southern Magnolia was found in 1993 by Thomas Julian Strickland. It was a plant among a batch of seedlings grown in 1989 from seed of the southern magnolia variety ‘Hasse’. The seedlings were growing at a nursery in Bulloch County, Georgia. Strickland noticed the superior root system when he grew cuttings from the tree, and soon saw the very narrow, columnar form of his plant. He named it ‘TMGH’ and patented it in 2000. Our plants are produced from stems taken from plants directly descended from that original plant, and they are genetically identical to it. Considering how very suitable this tree is for smaller gardens, and how hardy it is, we know that our stock will soon be gone – so order now and enjoy the beauty of the Alta Southern Magnolia.