Sweet gum, spherical amber tree – care and pruning

The ball sweet gum Liquidambar styraciflua ‘Gumball’, a small-stature variety of the sweet gum tree. Among other things, it impresses with a decorative, spherical crown. It reaches a height of about 3-5 m and develops a crown with a diameter of up to 4 m. Because of its small size, it is very suitable for entrance areas, for example, but also for a stand-alone position in the garden.

Due to its relatively strong branching, the spherical amber tree forms a relatively dense crown. When buying a spherical amber tree, the trunk has usually reached its final height. Over the years, the trunk just gets thicker, not taller. The crown, on the other hand, continues to grow.

planting

• Planting an amber or spherical amber tree is possible in spring or early autumn.
• Always ensure that there is sufficient distance to other trees!
• First the planting hole is dug.
• This should be twice as deep and wide as the root ball.
• Then drive a stake into this planting hole!
• This should be taken in the main wind direction.
• The stake gives the tree support and thus helps it to grow.
• Then mix the excavation with compost or bark humus!
• Fill the bottom of the planting hole with the mixed soil!
• Now plant the sweetgum tree!
• Place the tree in the ground about 10 cm below the grafting point!
• Fill in the soil and gently move the tree back and forth!
• This is important to eliminate voids in the root area.
• Then press the earth down or carefully step on it!
• When filling the soil, use a pouring rim if possible!
• Now fasten the tree loosely to the post with a rope made of coconut fiber, for example!
• Then water the whole thing thoroughly and cover it with a layer of mulch if possible!

location

The location should be as sunny as possible and sheltered from the wind and the soil should be permeable, fresh to moist, moderately rich in nutrients and slightly acidic. In very windy or drafty locations, the sweetgum tree loses its beautiful autumn leaves relatively early and quickly. In addition, wind breaks could easily occur.
Compacted soils are unsuitable, as the sweetgum tree would not tolerate them. The soil compaction should be eliminated accordingly if necessary. Soils that are too calcareous lead to yellowing of the leaves.

Watering and fertilizing

The sweetgum tree and its roots react very sensitively to drought, especially in the first few years. Waterlogging is just as bad as drought. You can fertilize every two weeks with a mineral fertilizer. Compost, for example, is a very good fertilizer.

Propagation by sowing or cuttings

Propagation by sowing
The sweetgum tree can be propagated using seeds as well as cuttings.
The best time to sow is in spring, from March and autumn. The seeds of the sweetgum tree may have to be stratified, ie subjected to cold treatment, especially if you have collected them yourself. In some cases, stratified seeds are also available.

For stratification, the seeds are first stored for 2-4 weeks in a dish in a moist substrate, for example made of sand, at room temperature. Then the whole thing is covered with foil and placed in the refrigerator for another 6 weeks. Then put it back in a warmer place at around 20 degrees until the seeds germinate.

Seeds that do not need to be stratified can be sown immediately in an appropriate growing container. Special potting soil or coconut fiber should preferably be used for sowing, both of which are low in nutrients and permeable to air. However, normal garden soil with about a quarter of sand is also suitable.

The seeds are spread on the moist substrate and only thinly covered with soil. Now the substrate must be kept evenly moist during the entire germination period. It shouldn’t be too wet, however. Then the cultivation vessel is covered with translucent foil or glass. About every three days, the film or the glass should be removed and the whole thing ventilated for a short time.

If the seedlings can be seen, direct sunlight should be avoided for the first 6 weeks. This is especially true for the summer months. The small seedlings can be repotted around 5 – 8 weeks after budding. You should proceed with particular care so that the fine roots are not injured or damaged.

Propagation by cuttings
The corresponding cuttings from older trees can be cut in spring or autumn. They should be about 10-15 cm long and have three eyes. Cuttings can be taken from a young sweetgum tree in July. These are then put into a substrate of peat moss and sand in equal parts for rooting. Once enough roots have formed, they can be transplanted.

Overwinter

In the first few years after planting, the sweetgum tree should receive appropriate winter protection in the area of ​​the roots. This can be a thick layer of leaves or fir branches. The trunk and treetop should be shaded if necessary.

From August onwards there should be no more fertilization so that the young shoots mature by winter and can easily survive the cold season. If you want to be sure, you can dig up very young trees before winter, plant them in a suitable container and overwinter in the house frost-free.
If you plant the sweetgum tree in spring, it usually has enough time to form and grow sufficient roots. Despite everything, in particularly cold winters it can happen that the budding, which usually takes place in May, is postponed.

It can also happen that a sweetgum tree planted in autumn may not survive winter. Buds or annual shoots can occasionally freeze, but they usually regenerate.

Older specimens are very hardy and can withstand temperatures of up to minus 25 degrees for a short time, provided that their location is protected.

To cut

Globe sweetgum ‘Gumball’

• The globe sweetgum tree is very easy on pruning.
• However, a cut is usually not required.
• The round crown grows in shape by itself and is then retained.
• In the case of older specimens, however, tapering the crown is recommended.
• If the crown becomes too dense, it can be thinned out.
• Do not cut in the spring when the juice is rising.
• Otherwise it can be cut or thinned at any time.

Sweet gum ‘Liquidambar styraciflua’
The sweet gum tree ‘Liquidambar styraciflua’ develops into an attractive sweet gum tree with a typical pyramidal crown, even without pruning. In rougher areas, it is more common for trees to be damaged during particularly severe frosts, for example entire shoots or shoot tips can freeze to death or die off. Then pruning measures are recommended. The same applies to long and dead branches and twigs.

Cut in April
After winter, frozen twigs or shoots can be cut back into the living wood. April is very well suited for this, because then the new shoot has started and you can see the damaged areas very well, because there are no more new leaves growing there.

Cutting in summer
When cutting in summer , for example, branches that are too low can be removed. The branches must not be cut too close to the trunk, the branch collar should be retained. The branch attachment point on the trunk is known as the branch collar. When sawing off a somewhat thicker branch, it is advisable to first saw a notch below the branch and then saw off the branch from above. Finally, cut off the stump and ensure there is sufficient distance from the trunk.

Cutting in autumn and winter
In autumn / winter the best time is to cut back branches that have grown too long or to thin out the crown, but only in frost-free weather. With this cut, thicker branches are cut evenly over the entire crown, if possible without tearing individual branches. Here, too, it is advisable to always first saw a notch from below and then to saw it off again from above. As a result of the cut, new branches and leaves form in the crown, making it denser. After the cut, it is important to treat the cut wounds with an appropriate wound closure agent.

Diseases

The sweetgum tree is resistant to almost every pest. Only young trees can sometimes be infected with aphids. Older people usually no longer experience this problem. Otherwise, only the roots are usually susceptible to disease. But this is usually the result of inadequate or incorrect care.

Aphids
The aphids can be seen on the leaves, along the leaf veins. Depending on which aphid species it is, it can also lead to more or less strong honeydew excretions. Stronger leaf shedding is usually not to be feared. Appropriate agents for controlling aphids on ornamental trees can be used to control aphids.

Special features of the sweetgum tree

The flowers of the sweetgum tree are relatively inconspicuous. They appear for the first time after about 20 years and sit on long, thin flower stems, the female flowers are arranged in chestnut-like, drooping balls and the male flowers consist of about 5-7 cm long spikes or grapes.

The fruit clusters emerging from the flowers contain numerous capsule fruits. These are heavily lignified and in turn contain a large number of tiny seeds. However, in Central Europe the seeds and fruits of the sweetgum tree do not ripen in most cases. Much of the seeds are sterile.

The alternately arranged, five- to seven-lobed leaves are similar to those of the maple. The more inconspicuous the flowers, the more impressive the autumn colors of the leaves. The sweetgum tree is a very popular wood, mainly because of this splendid autumn color that sets in relatively early. The bark of this tree is initially red-brown and later turns gray-brown. It has deep furrows and the branches of older plants have irregular, decorative cork strips.

Conclusion
The sweetgum tree is a particularly attractive and decorative tree. The smaller spherical amber tree in particular is a highlight in every garden, front yard or entrance area due to its small size and impressive autumn colors. It is very robust and easy to care for, provided the site conditions are optimal and there is sufficient watering.