Evergreens as street trees in Israel

Along with this preference, we primarily tend to use fast-growing trees. We lack the patience to wait the years necessary before we can enjoy the adult tree. Its volume, shade, full foliage, flowers (in trees that have significant flowering), handsome trunks that one finds in different species, etc. In this way, many special and valuable species that improve over the years have been pushed off the streets, from where they are now sorely lacking, such as Quercus, Acer, Pistacia, Liquidambar and Magnolia species, as well as Pararchidendron pruinosum.

It’s not easy being evergreen

However, this combination is a mixed blessing. Fast-growing evergreens may be too large and invasive so that it impedes their adapting to urban spaces. An example of this are large eucalypts (Eucalyptus camaldulensis, Corymbia torelliana, Corymbia citriodora or Eucalyptus leucoxylon) and different kind of fig trees (Ficus microcarpa, obliqua, rubiginosa and more). Their tremendous capacity for growth demands great attention and intensive care from us in design and pruning. Over the years, these trees will raise sidewalks and are likely to damage underground infrastructure in their surroundings.

Other evergreens, such as Alectryon tomentosus, Harpephyllum caffrum and Cupaniopsis anacardioides, have juicy fruit that is very messy and attracts birds, which further dirty the area with their excrement. Not to mention Kigelia africana (the sausage tree), whose large and heavy fruits endanger anyone walking beneath it. There is also concern regarding Lagunaria patersonia’s fruit, which causes skin irritation on contact. Its sensitivity to sooty mold also reduces its quality as a street tree.

It is important to also mention Fraxinus uhdei, even though this is not an evergreen. On the face of it, this is an excellent street tree, and as a result it is one of the most common in Israel. It has a particularly fast capacity for growth and is known for its branches at acute angles. In Israel, people who work on these trees tend to neglect their pruning and designing, which is especially important in its early years. The result is unbalanced adult trees with too many branch pressure points due to branches emerging from the same place from the trunk and the central structure of the tree.

The ‘helplessness’ of not having enough resources to care for Fraxinus uhdei makes the boulevards of these trees dangerous, with the potential branches breaking only increasing over the years. Furthermore, nearly all Fraxinus trees planted in Israel are propagated from seeds. As a result, boulevards are not uniform in terms of canopies, tree size, leave shape, fruit appearance and fall display.

Brachychiton populneus is another good example of a tree with unrealized potential to be an excellent street tree. Unfortunately, its use as such has nearly ceased. Both because of poor design by nurseries over the years (the marking of the growing shoot apex and the inhibition of apical dominance) and because the tree was propagated from seeds, which created a great variance between the individuals, reflected in the shape of the leaves, the size of the canopy, the color of the flowers and even the color of the trunk.

Quercus calliprinos, Q. ilex or Q. suber are messy, and their acorns are a slipping hazard; moreover, they don’t grow quickly. Acer obtusifolium, Pittosporum undulatum, Podocarpus falcatus or Arbutus unedo can be impressive street trees, but only in adulthood. Until that point, they grow slowly and only reach their full beauty after years of proper design and care.

So we tried to be clever: we designed species that are actually shrubs in nature, and we tried to turn them into ornamental trees for our streets. In some cases, it worked partially, like with Ligustrum japonicum, Callistemon and Homalanthus populifolius. These are trees with shrub-like natures and a medium capacity for growth with the potential to be excellent small street trees. But they require optimal conditions and continuous care. Without these, we see the trees fail and degenerate. As a result, their use as street trees is coming to an end, and that’s a shame.

Other plants like Hibiscus tiliaceus ‘Sitriya’, Tecoma castaneifolia ‘Hagar,’ Calliandra haematocarpa and Schinus terebinthifolia are more commonly used due to their higher capacity for survival and speed of growth. But this pro comes with a serious con. Similar trees require intense care and repeated pruning during their first years until they establish a strong framework. But an “independent” framework cannot be built on these trees because of the form of pruning. Therefore, in this case, it’s an eternal issue. Always, every fall, it will be necessary to prune them again.