The Katsura is a dioecious plant, producing male and female flowers on separate trees. Its flowers are inconspicuous and unremarkable but red flowers indicate a male plant and green flowers identify the female plant. It grows best when planted in late winter or early spring. It is nicknamed the “caramel tree” for its sweet, caramelized sugar or cotton candy fragrance in the fall. This tree grows best in evenly moist soil, A 3 inch layer of mulch over the soil surface after planting will help retain moisture. An added benefit of organic mulches, like bark mulch, is that they deliver nutrients to the soil and improve drainage as they break down.
Light
Katsuras can be grown in partial shade because they are understory trees (a tree that grows under the canopies of larger, taller trees) in the wild. For trees that grow in the southern or hotter areas of their range, plant them in a location that receives some shade to prevent their leaves from getting scorched in the summer. In the North, give them full sun, and they will achieve better fall foliage color.
Soil
This tree prefers enriched soil that is well-drained and relatively moist with a neutral to slightly acidic soil pH. However, the Katsura can also tolerate clay soil, acidic soil, and salty soil.
Water
Katsuras have moderate watering needs overall, roughly 1 inch of water per week, but may need more frequent watering in dry areas. Water as required to keep the soil moist (but not wet) until the tree is well established. Once established, it becomes somewhat drought-tolerant.
Temperature and Humidity
Suitable for zones 4 to 8, this tree can tolerate a relatively broad temperature range and is not too picky about humidity. In damp climates or rainy seasons, avoid overhead watering to prevent leaf mildew.
Fertilizer
Fertilize newly planted saplings using a higher nitrogen mix fertilizer (20-20-20 NPK). As the tree grows and becomes established, use a balanced, general-purpose fertilizer (10-10-10) and soak the ground well afterward to ensure that the fertilizer goes down to the roots. You can use granular, liquid, or stake fertilizers; follow the package instructions. In general, fertilize once a year in late fall or early spring before buds develop.
Types of Katsura Trees
‘Red Fox’ Katsura tree (Cercidiphyllum japonicum ‘Rotfuchs’): Mid-size variety (30 feet tall, 16-foot spread); one of the most colorful types, bearing purplish-bronze leaves in spring, greenish-bronze leaves in summer, and orange-bronze in fall ‘Ruby’ Katsura (Cercidiphyllum japonicum ‘Ruby’): Small (30 feet tall); sports blue-purple leaves ‘Dawes Ascension’ Katsura (Cercidiphyllum japonicum ‘Dawes Ascension’): On the taller side for Katsura (50 feet); has a columnar shape for the first decades of life; green-blue leaves turn apricot yellow in fall Dwarf varieties ‘Heronswood Globe’ Katsura, ‘Glowball’ Katsura, ‘Boyd’s Dwarf’ Katsura, ‘Herkenrode Dwarf’ Katsura, and ‘Kruckeberg Dwarf’ Katsura: Smallest of the cultivars, topping out at 8 to 15 feet Weeping Katsura tree (Cercidiphyllum japonicum ‘Pendulum’): 15 to 25 feet high, with a similar to slightly greater spread; branches of this smaller type droop down, adding visual interest
Pruning
Full-grown Katsuras typically do not need pruning other than seasonal cleanup and maintenance. Begin shaping the growth of the tree when it’s young. The best time to prune is in the late fall after leaves have dropped or early spring before it produces sap. Remove crossing or crowded branches. Also, you can remove low branches, no more than one or two per year, to provide clearance under the tree. After the tree is established, it should only need pruning every three to five years. Check the tree each spring, and remove any suckers or dead branches.
Propagating Katsura Trees
Katsura trees are best propagated from seeds, but they can also be grown from stem cuttings or suckers during late spring. A stem cutting is propagated from a healthy stem of softwood or semi-hardened stem. Using sterilized scissors or pruners, take a cutting 6 to 8 inches long that has four to eight leaf nodes. Remove all the leaves except for the two topmost sets. If the Katsura tree has suckers or offshoots growing from the base of the tree, you will have a greater rate of propagation success. Using a sharp, sterilized blade make a notch 1 inch below the sucker. As you pull or peel off the sucker, you will get some bark with the basal cutting. Notching will prevent without excessively damaging the tree and givie it a better chance of healing cleanly. If you neglect to notch the trunk, too much bark can peel and injure the tree.
How to Grow Katsura Trees From Seed
Katsura trees have the most significant growing success when grown from seeds. Collect seeds from fallen pods in the fall. Germination is almost 100% guaranteed when the seed pod has freshly fallen. Sow the seeds immediately indoors in nursery pots for best results. If you get seeds from a nursery or another source, stratify them by keeping them in a moist towel in the refrigerator for eight days. Another method is to expose the seeds to light for 15 hours a day for three weeks while kept moist on a paper towel. Plant two to three seeds 1/4 inch deep in a pot of moistened all-purpose soil or seed starter mix. Cover the pot with clear plastic wrap to keep in moisture and promote germination. Place the pot in a bright, indirectly lit spot. Germination usually takes eight to 12 days. Let the plant grow for at least four to six weeks before transplanting into the ground or wait until spring after the threat of frost is gone.
Overwintering
Protect young trees from the winter sun by using a commercial-grade tree wrap around the sapling’s trunk for the first few winters. Wrap it in the fall after leaves have fallen and remove it in summer once the leaves grow back in.
Common Pests & Plant Diseases
This plant is relatively disease and pest-free. It may develop powdery mildew in very humid, warm climates. This mold looks like a light velvety white layer or white spots on leaves. Water at ground level at the trunk and along the drip line to prevent mold and avoid wetting the leaves. You can remove and discard badly affected leaves or branches to reduce powdery mildew or apply a fungicide, Katsura trees are also deer resistant.
Common Problems With Katsura Trees
Katsura trees are hardy trees with very few issues that affect their growth. Picking a suitable planting site is perhaps the most essential factor for maintaining good health.
Browning Leaf Edges, Yellowing Leaves
If the leaf edges are turning brown and the center of the leaves are yellowing before the fall season, your tree may have leaf scorch. Dry weather, high winds, and exposure to too much sun can cause leaf scorch. You may notice the leaves falling in late summer rather than the fall. The placement of this tree is crucial in preventing leaf scorch; it can benefit from some shade from taller neighboring trees or wind protection provided by buildings or other trees. Watering your tree deeply and providing adequate mulching around your tree can also prevent leaf scorch from worsening.
Split Tree Bark
Bark can split from environmental stress due to temperature fluctuations, high winds, or excessive growth in autumn from too much fertilizer. Trim off the dead bark, but be careful not to pull off any remaining healthy bark. Water deeply but do not allow the soil to get soggy and apply organic wood-based mulch once every couple of years.
Sudden Tree Wilt
A stem canker caused by a fungal or water-mold infection can cause sudden tree wilt. The leaves will suddenly turn brown, start shriveling, and fall off. This infection is most likely from overwatering or too much rain or moisture. The condition may originate in the roots and root crown below the soil. At this advanced stage of deterioration, it may be difficult for the tree to survive. You can reduce watering, but nothing but time can say if your plant will rebound in the next growing season.
