Tor Spirea
Spiraea betulifolia var. aemiliana ‘Tor’View more from Spirea
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Botanical Name
Spiraea betulifolia var. aemiliana ‘Tor’
Outdoor Growing zone
4-8
Mature Height
2-3
Mature Width
2-3
Sun needs
Full Sun
The Tor Spirea is a dense, mound-forming small shrub growing to around 3 feet tall and wide. It is covered in clusters of sparkling white flowers in May and June, and in fall it has the best colors of any spirea, turning gold, orange and red. In between the cool green leaves are the perfect backdrop to summer plants. Use it in front of evergreens, on slopes and in rock gardens, in clusters or drifts in shrub beds, and as a low hedge. Trimmed or not it will always be neat and tidy.
Full sun is best for your Tor Spirea, which is hardy all through zone 4. It grows in any ordinary well-drained soil, and it’s drought resistant once established. Free of pests or diseases, and deer also leave it alone. Prune in late winter before flowering, if needed, and/or trim lightly immediately after the blooms are over. A very low-maintenance shrub.
Every garden needs reliable, easy shrubs to give bulk and form to your beds. Sometimes these plants are not so exciting, or only have one brief time of interest. That’s why we love the Tor Spirea, because it’s lovely from spring to fall. Let’s start with the attractive dark-green leaves that always look healthy and clean, giving a dense plant right to the ground. Then we can move on to the brilliant show of pure-white flowers in May and June, lasting weeks and sparkling bright. Then we arrive in fall, when this is by far the best spirea of all, with terrific gold, orange and red foliage that makes a fabulous display. While admiring all this beauty, we can’t forget just how easy and reliable this plant is, and how little it will take for you to enjoy it in your garden. Talk about value – unbeatable displays twice a year, cold-hardy, easy-care and always attractive – sounds like the perfect garden shrub, no
The Tor Spirea is a small, rounded, deciduous shrub growing 2 to 3 feet tall and wide. It forms a dense, bushy plant with many small twigs, growing right to the ground. Untrimmed it could reach 4 feet tall in time.The slender zig-zag stems are dark reddish-brown and glossy when young. The small egg-shaped leaves resemble those of birch trees, and they are about 1½ inches long and smooth, with a triangular base and rounded teeth towards the tip end. Spring leaves are light green, quickly darkening to an attractive green with a slight bluish cast to it. The foliage stays clean and attractive at all times. In fall they turn wonderful shades of yellow, orange and red, with the strongest coloring developing in cold zones and full sun. The leaves are too small to make a litter problem, and soon disappear. In May to June rounded heads of flowers develop all over the bush, at the ends of new shoots. These are 2 to 2½ inches across, packed with many tiny blossoms. These have 5 rounded petals forming a shallow bowl, with fuzzy stamens that are pale cream. The brilliant white coloring really stands out, making a sparkling display. Flowers are followed by insignificant seed heads that disappear beneath the leaves.
For a compact dwarf shrub, the Tor Spirea can’t be beaten. It is perfect for the front of shrub beds, with leaves right to the ground. Plant it among the evergreens around your house for color, or among summer-blooming shrubs. Use in for mass-planting in larger beds, in groups and drifts – space plants 18 to 24 inches apart. Plant a row at 18-inch intervals for a great hedge, with or without trimming. Use it to fill spaces in a rock garden, or among boulders on a slope. It is even small enough to grow in large planter boxes with other small shrubs.
The Tor Spirea is exceptionally hardy, growing well in zone 4, and through all but the hottest areas, into zone 8.
Full sun, or nothing more than an hour or two of shade each day is best for the Tor Spirea. Too much shade will make it floppy, with few flowers and poor fall color. It grows easily in all kinds of soils, as long as they are well-drained. In cooler zones it tolerates drier conditions – in hot zones moist soils are preferred. Once established it is fine in ordinary dry summer conditions – it will even encourage the strongest fall colors.
Free of pests and diseases, and not eaten by deer, you should have no problems with this shrub at all. It belongs to the group of spirea that bloom on new stems, so prune in late winter as needed, removing a few of the oldest stems low down, and shortening younger ones for neatness. In actual fact it rarely needs much pruning, and can be ignored for years. A light trim after flowers – just enough to remove the spent flowers – is OK if you are a very neat gardener.
Birch-leaf spirea, Spiraea betulifolia, is a species divided into four distinct varieties, with two of them (var. corymbosa and var. lucida) found growing wild across large parts of North America. In Alaska, British Columbia, eastern Russia and Japan, a compact variety called Spiraea betulifolia var. aemiliana is found, and it is this variety that is the parent of ‘Tor’. The word ‘torr’ in Swedish and Norwegian means ‘dry’, a reference to dry rocky places, giving us the British-English word ‘tor’, which means a rocky hill, perhaps a reference to the shrub’s mounded shape. We don’t know much about its origins, but it seems to have first appeared in America at the JC Raulston Arboretum in Raleigh, part of the University of North Carolina, who offered it as a new release in 2002. They apparently obtained it from a Scandinavian source. It is notable for its more compact shape, cold resistance and excellent fall coloring.
It’s important to build a backbone of reliable and easy shrubs in your garden – leaving you free to plant and nurture the trickier stuff. The Tor Spirea is perfect for all your ‘easy small shrub needed’ locations, but order now, as this variety is not widely available, and it won’t be around for long.