Judas tree (Cercis siliquastrum) is a small deciduous tree indigenous to Southern Europe and Western Asia. The judas tree is pollinated by bees. This species is protected in Israel. It grows best in deep, well-drained soils in full sun or partial shade.
I. Appearance and Characteristics
Cercis siliquastrum , commonly known as the Judas tree or Judas-tree, is a small deciduous tree in the flowering plant family Fabaceae which is noted for its prolific display of deep pink flowers in spring. It is native to Southern Europe and Western Asia.
The species was first described by Linnaeus in 1753 and he gave it the specific epithet of siliquastrum which is derived from the Latin word siliqua, meaning “pod”. The generic name comes from the Greek kerkis, a “shuttle”, which refers to the resemblance shown to this weaver’s tool by the flat, woody seed pods.
This species forms a small tree up to 12 m (39 ft) in height and 10 m (32 ft) in width.
The deep pink flowers are produced on year-old or older growth, including the trunk, in spring. They have five free petals and fused sepals, a flower shape typical of much of the pea family (Fabaceae). The leaves appear shortly after the first flowers emerge. These are cordated with a blunt apex and occasionally have a shallow notch at the tip. The tree produces long flat pods that hang vertically. The flowers are edible and reportedly have a sweet and tart taste.
The flowers are pollinated by bees, which are attracted by nectar. Pollen from the protruding stamens is deposited on the bee’s body and carried to another flower’s stigma.
In Israel the tree has a status of a protected plant.
British journalist Francis McCullagh reported seeing “innumerable” flowering specimens of this tree in Yildiz Park in Istanbul in April 1909.
II. How to Grow and Care
Sunlight
Eastern Redbud responds well to direct sunlight and does best in partial shade, whereas Western Redbud thrives in full sun. That’s why judas tree is found in a variety of moist, well-drained soils, and grows more densely on sunny slopes where it enjoys more intense sunlight with less plant competition.
Temperature
Judas tree adapts to wide fluctuations in temperature and growing environment, ranging from -28 ℃ in the winter to 32 ℃ during summer. To induce flowering, judas tree needs temperatures below -2 ℃. Some research reports it can withstand 40 ℃. Judas tree grows in areas with an annual rainfall of 51 to 127 cm. It needs sufficient water for its growth and is somewhat resistant to drought.
Watering
Eastern Redbud trees planted in full sun respond well to watering. Keep the soil moist during the summer. Apply a little watering to young plants initially; their watering need will increase as they grow. For better moisture preservation, polythene mulch can be spread on the beds, making holes in the mulch at the point of plant emergence.
Western Redbud is more tolerant of prolonged periods of drought but responds well to watering during dry conditions. For more vigorous, lush green sprouting, water regularly if planted in direct sunlight.
Soil
Eastern Redbud can well grow outdoors in moist, loamy, or sandy soils. Its occurrence on slopes with more sunlight is prevalent. It is acclimatized to a wide range of pH; however, it thrives best with a pH range of 6.6-7.8 or above. It doesn’t tolerate inundated sites, poorly aerated soils, or sandy soils.
Western Redbud is adapted to grow in a wide variety of soils, including course and nutrient-deficient soils that are well-drained. It grows as an understory cover tree and is fairly tolerable to lime and acidic soils. It also tolerates alkaline soil and clay; its best pH range is 5.5-7.8.
Fertilizing
Being a member of the pea or Leguminosae family, judas tree can fix nitrogen, so there is no need to add nitrogen fertilizer to these plants because excessive nitrogen application invites caterpillars and sucking pests to your plants. Add some compost in the soil before planting to help extend moisture retention.
At the time of planting, mix phosphorus supplementation with planting soil to help roots develop. As judas tree is primarily planted due to its clustering flowering patterns, boost flowering by applying fertilizer rich in boron to leaves at the start of the spring.
Planting Instructions
Judas tree is fairly easy to propagate by direct sowing. It can also be grown in a container during spring or fall.
Collect seeds from pods with a dark brown or reddish-brown color, as this indicates the maturity of the seed pods. Preserve seeds in an airtight container at 3 ℃. The hard outer seed covering requires seed scarification and stratification to break dormancy. Put seeds in steaming hot water for 30 minutes and follow moist sand stratification for 6-8 weeks at 5 ℃. Seeds are now ready to be planted during the current fall or upcoming spring.
Dig the soil to a depth of 30 cm; make a fine tilth that allows the young roots to easily penetrate it. Judas tree has a tap root system that grows quickly during the first year. Bed size can be adjusted depending on the available space. During late spring, put your seeds in the bed to a depth of 4 to 5 cm and cover gently with garden soil. Seedlings or already growing plants can also be planted in prepared beds adopting the “balled and burlapped” method.
Pruning
Judas tree requires regular pruning for pedestrian clearance beneath the canopy, as it usually branches low on the trunk. The tree grows in a multi-trunk fashion that can be trained to continue with a single dominating trunk. Trees must be pruned to remove overcrowded branches, weak branches, forks, and dead limbs to give its canopy a rounded, vase shape that adds value to your garden landscape.
Prune at the appearance of new leaves or in the late fall. Reduce the number of lateral branches and maintain a reasonable distance between them.
Transplanting
The optimal period to transplant judas tree is during its ‘leafless rest’ period, often during late autumn to early winter. This period permits uninterrupted root growth. Judas tree enjoys well-drained soil in sunny to partial shade locations. For smoother transplanting, ensure the root ball is properly moist before moving.
Pests and Diseases
The tree is susceptible to leafhoppers, scale insects and psyllids (specifically Cacopsylla pulchella) as well as diseases including canker, coral spot and verticillium wilt.
Maintenance
Inspect your plants regularly for signs of the common diseases. Remove plant debris, fallen and broken branches, and dead leaves from your garden. Focus on irrigating your redbud plants during a severe drought in summer.
It’s best to grow judas tree with locally harvested seed due to its adaptability to local conditions. Such plants are more resistant to the local environment and perform better than seeds from other sources. Focus on plant health by adding essential nutrients and fertilizers recommended for your area.
III. Uses and Benefits
- Ornamental uses
Consider the judas tree for street planting or growing in a low-maintenance shrub garden for its stunning purple or pink flowers, which bloom before the leaves appear in early spring. This tree also makes a lovely understory tree when planted beneath tall trees in large, wooded garden sites.
- Medicinal uses
The Judas tree is referred to as a traditional Palestinian medicinal plant.
Find Where to Buy the Best Judas Tree (Cercis siliquastrum)
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