Tor birchleaf spirea is a deciduous shrub that is native to eastern Asia. It is a member of the rose family and can grow to be 6-8 feet tall. The leaves are ovate and have toothed margins. The flowers are white and borne in clusters. The fruit is a dry, brown capsule.
Related plant:
Hydrangea Paniculata Diamant Rouge
Related plant:
White Chiffon Rose Of Sharon
About soil condition, the Tor Birchleaf Spirea prefers well-drained soil, but will also tolerate clay or sand. The plant is adaptable to both dry and moist conditions, but does best in moist, well-drained soil. It is also tolerant of salt.
So, like the other spirea bushes, thetor birchleaf spirea require full sun to partial sun. They prefer well-drained, moist soil but can tolerate a wide range of soil types as long as it is not waterlogged. Be sure to provide plenty of room for this bush to grow, as it can spread up to 8 feet wide.
The temperature condition that is best for the growth of the tor birchleaf spirea is a temperature that is cool to cold. This plant does not tolerate heat well and will not grow in temperatures that are too warm. The ideal temperature range for this plant is between 45 and 65 degrees Fahrenheit.
Ideal humidity condition for this plant is between 40 to 60 percent. If the humidity level drops below 40 percent, the leaves will start to drop off. If the humidity level rises above 60 percent, the leaves will start to yellow.
The fertilizer, this family of plant is undemanding and quite tolerant of poor soil, but still benefits from being fertilized in early spring. A general-purpose fertilizer will suffice. Avoid getting the fertilizer on the foliage to prevent leaf scorch. Because of its suckering habit, it is best to apply the fertilizer to the root area only.
Pruning is generally not necessary for tor Birchleaf spirea, as it is a naturally tidy shrub. However, if you wish to tidy it up or control its size, you can trim it after it blooms in late spring or early summer. Simply cut back the stems that have flowered, to just above where new growth is emerging.
Propagation is normally done by rooting softwood cuttings taken from the tips of the current year's growth in late spring or early summer. Hardwood cuttings can be taken from well-established plants in late fall or early winter.
Usually, the plant growth rate is slow to medium. In the wild, these plants can grow up to 3 feet (91 cm) per year. But when grown in the home landscape, they typically grow only 1 to 2 feet (30-60 cm) per year.
Common problems for this kind of plant are powdery mildew, rust, and anthracnose. These can all be controlled with proper fungicide application. Another problem that can occur is leaf spot, which is caused by a variety of fungi. This can be controlled with proper fungicide application as well.
Source:
JC Raulston Arboretum - Our Plants - Spiraea betulifolia 'Tor'
Free Tor EDU Event Series Aims to Demystify Publishing
Tor, What Is It Good For - cyberTAP Blog - Purdue University