Spiraea betulifolia tor is an erect, deciduous shrub that typically grows to 6-9 (less frequently to 12) tall with a similar spread. It is noted for its ovate-lanceolate, toothed, dark green leaves and clusters (corymbs) of pinkish-white flowers that bloom in mid-spring.
Related plant:
Spiraea Grefsheim
Related plant:
Spiraea Japonica Shirobana
About soil condition, Spiraea betulifolia Tor requires well-drained soils and does not tolerate flooding. It prefers sandy or gravelly soils and can grow in loamy soils. It cannot tolerate heavy clay soils.
Like the other Spiraea betulifolia, the 'Tor' has beautiful white flowers that bloom in the spring. It is a deciduous shrub that is best planted in full sun. It grows to be about 3-4 feet tall and wide, making it a great choice for smaller gardens. The 'Tor' is also quite tolerant of drought and clay soils, making it a low-maintenance plant.
The temperature condition that is required for the growth of Spiraea betulifolia tor is a cool climate. This plant is native to the northern hemisphere and is found in North America, Europe, and Asia. It prefers cool, moist conditions and does not tolerate heat or drought well. In the wild, it is often found growing in damp, shady areas such as along streams or in forest understory.
Ideal humidity condition for this plant is 60-70%. If the humidity is too low, the leaves will start to curl and the plant will become dormant. If the humidity is too high, the leaves will start to yellow and the plant will become stressed.
Discussing fertilizer, this plant does best with a 1/2 pound of 10-10-10 fertilizer per 100 square feet of garden space. However, too much nitrogen will cause the plant to produce more leaves than flowers. The best time to fertilize is in early spring, before the plant begins to produce new growth. For organic gardeners, compost or well-rotted manure can be used in place of chemical fertilizer.
Pruning is an important part of keeping your spiraea betulifolia tor healthy and looking its best. While the plant doesn't require pruning, it can help to control its size and shape. Pruning also encourages new growth, which can help keep your plant looking full and lush. To prune your spiraea betulifolia tor, start by removing any dead or dying branches. Next, trim back any overgrown branches to encourage new growth. Finally, shape the plant by trimming back any stray branches.
Propagation of Spiraea betulifolia Tor is generally by seed, although softwood cuttings can be taken in late spring. Sow seed in a cold frame as soon as it is ripe in September or October. Place the seed trays in a shady position and protect from frost. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a cold frame for their first winter. Plant them out into their permanent positions in late spring or early summer. Softwood cuttings can be taken in late spring and rooted in a cold frame.
Usually, the plant growth rate is relatively fast, with the plant being able to add about six inches to its height each growing season. However, some growth may be stunted during periods of drought or other environmental stressors.
Common problems for this kind of plant are diseases such as rust, powdery mildew, and leaf spot. These can be controlled with fungicides. Another problem is aphids, which can be controlled with insecticides.
Source:
JC Raulston Arboretum - Our Plants - Spiraea betulifolia 'Tor'
Spiraea betulifolia | Chadwick Arboretum & Learning Gardens
Spiraea betulifolia | UW Libraries Digital Repository
