Flowering time (month)
Ornamental or utility value
nectar or pollen plant
dry to moderately dry
alkaline to slightly acidic
The common Judas tree (Cercis siliquastrum) belongs to the carob family (Caesalpiniaceae) and within this family to the genus Judas trees. There are about ten different species worldwide, of which two are native to North America and the rest to West and East Asia. The common Judas tree is the most important gardening tree. It is native to southern Europe, Asia Minor, Persia and Afghanistan. It grows in forests and on river banks, but also in dry corridors on predominantly calcareous, often stony soils with moderate nutrient content. Legend has it that Judas Iscariot hanged himself from such a tree after betraying Jesus to the Romans.
The common Judas tree grows as a large shrub or small tree and forms an expansive umbrella-like crown with age. In the youth it grows however rather upright. He sometimes branches out a little sparse. Depending on the climate and location, the shrubs grow to four to six meters high and just as wide. They grow relatively slowly, about 25 to 30 centimeters per year. The bark of the younger shoots shines blackish brown, the bark of the trunk and the older branches usually shows an olive green colour with fine reddish brown longitudinal cracks.
The leaves of the common Judas tree are alternate, deciduous and rounded to kidney-shaped. They are seven to twelve centimeters long and approximately the same width. The upper side shines slightly bluish green, the underside is matt grey-green. In autumn the leaves show a beautiful golden yellow to orange-red hue. In the Orient the edible flowers are used to decorate food and salads.
The bright pink butterfly flowers sit in small bunches on the perennial shoots and also form directly on the stem – botanists call this phenomenon cauliflory. They sprout in front of the leaves from the beginning to the middle of April and seem to cover the entire wood in a pink cloud.
The fruits of the common Judas tree are ten to twelve centimeters long, first green, later light brown pods. They are very similar to sugar peas and often stick until spring. In contrast to the flowers, the fruits are slightly poisonous.
The flowers of the common Judas tree partly sit directly on the trunk and on the larger branches (left), the seed pods from the previous year often still stick to the branches in spring during the flowering period (right).
Location and soil
The common Judas tree needs a full sunny, warm and somewhat protected location. It grows best on sandy, well-drained clay soils, which should be moderately dry to dry and rich in lime. However, it also grows on weakly acidic soils and tolerates longer periods of heat and drought without any problems.
Planting and care
Since the Judas tree as a young plant is somewhat sensitive to frost, it is best to plant it in a protected location in spring. After the tree has grown in well, it no longer needs any care at all – neither fertilizer nor water. In winter you should mulch young Judas trees thickly with autumn leaves to be on the safe side and additionally protect the main branches from the winter sun to avoid frost cracks.
It is possible to cut Judas trees, but this is only necessary for very young plants for crown correction. The shrubs do not age, become more beautiful over time without pruning and bear more and more flowers from year to year.
Use in the garden
In any case, give the ordinary Judas tree in the garden a single box seat and make sure that it has enough room in all directions to develop its picturesque crown. The perfect location is a large rock or rock garden, where the Judas tree can be combined with various other drought-loving ornamental shrubs, wild tulips and rock garden shrubs. But even a place in a normal garden soil is good for it, as long as the soil is permeable and not too damp. Here it can be very well underplanted with the most diverse forest edge shrubs, because on the one hand it has a tolerant root system and on the other hand its bright crown lets enough sunlight through.
The common Judas tree is usually only offered as wild form and as variety ‘Alba’ with white flowers. However, the related Canadian Judas tree (Cercis canadensis) – which in contrast to its name is native to the east coast of the USA – has special garden forms with special characteristics: ‘Forest Pansy’: a red-leaved variety with heart-shaped leaves, with a height and width of six to eight metres it is slightly larger than the common Judas tree and is also a vigorous ‘Lavender Twist’: hanging form, two to five metres high and three to four metres wide ‘Hearts of Gold’: yellow-leaved variety
Cercis siliquastrum ‘Alba’ (left), Cercis canadensis ‘Forest Pansy’ (right)
From the Chinese Judas tree (Cercis sinensis) the variety ‘Avondale’ is commercially available. It looks very similar to the common Judas tree, but is only 1.5 to 2.5 metres high and is therefore well suited for cultivation in tubs on the terrace.
The wild form of the Judas tree is increased above all by sowing, the garden forms of the other types by grafting. Most common is the oculation on seedlings of the common Judas tree, but also the copulation in late winter is practiced.
Diseases and pests
The common Judas tree is one of the few trees that are almost free of diseases and pests. In warm and humid weather, infestation with leaf spot diseases may occur in rare cases, but these are no longer a cause for concern. If young Judas trees are heavily infested, you should use a commercially available fungicide.
Judas tree in the our store-Shop
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.