It Really is All About the Trees

It really is all about the trees.
Most of the correspondence sent my way involves trees.  Questions about fruit trees, especially citrus trees, are the most common.   Suggestions are also sought for fast growing shade trees of manageable size (silk tree or Albizia julibrissin, for example), for trees that grow in limited space (‘Little Gem’ magnolia tops the list), and for trees that can serve as hedges (‘Oro Blanco’ grapefruit trees serve that purpose admirably and provide fruit as well).
In the pantheon of horticultural pleasures, fragrant flower bouquets are without equal, but memories depend on trees.  You will more likely associate your childhood with what happened under the oak tree than with what transpired beside the petunia patch.
Trees with glorious flowers are particularly evident this time of year and it struck me all of a sudden that the botanical family, now and throughout the year, with the most flowering species by far is the legume family (Fabaceae).  Leguminous trees manufacture their own nitrogen fertilizer and perhaps this is the key to their success.  All legumes, from peas to carob trees, are recognizable by their pods.

Western redbud (Cercis occidentalis) at Van Nuys-Sherman Oaks Park

Let’s start with Western redbud (Cercis occidentalis), the first tree to flower in the spring.  In full bloom, this species presents as a blinding flash of magenta-pink against a background of smooth gray branches. Before a single leaf appears, branches are studded with flowers. And if the flowers themselves are not sufficient to keep your interest, a display of heart-shaped leaves, infused with bronze, are soon to follow. Eventually, these leaves turn to a pleasant lime green and, in the fall, will change to gold, orange and red.

orchid tree (Bauhinia sp.) at Chandler Elementary School, Sherman Oaks

white flowered orchid tree

Orchid trees (Bauhinia spp.) are leguminous kin to redbuds and, like them, flower at this time of the year. You really have to get up close to appreciate orchid tree flowers. From a distance, all you see is their pink to purple colors. Close inspection reveals their corsage dimensions, best appreciated by floating them in a bowl on your dining room table.  Occasionally, you will see a white flowered specimen, a type that I prefer because it is rarely seen and, nearly always when it comes to plants, the exotic prevails over the prosaic when it comes to favorites since the eye simply grows tired of seeing the same thing over and over again.

Acacia tree in bloom

Acacia trees, legumes native to Australia and East Africa, put forth golden yellow flower puffs at this time each year. Acacias grow quickly, even in compacted soil, and require little water; at maturity, they are no more than 25 or 30 feet tall. A good example is Acacia baileyana, the golden mimosa. Its blue-gray feathery leaves impart an unparalleled softness to the tree’s canopy. Acacia baileyana purpurea is a variety with distinctive violet-tinted foliage.  Knife acacia (Acacia cultriformis) has fascinating triangle-shaped leaves, and Sydney golden wattle (Acacia longiflora) produces scads of flowers in pendant, butter-yellow chains.

Tip of the Week:  Ernest Scarcelli, who gardens in Van Nuys, has a large lemon tree over 60 years old and wants to know what is the best time of the year to prune it.  My advice is to prune now, before summer temperatures arrive.  Following pruning, newly exposed branches could burn in scorching heat.  In addition, insect pests and fungi  that are attracted to sap seeping from pruning cuts are more active in summer.  Another favorable time to prune would be in the fall, after lemon harvest.  Keep in mind that pruning stimulates new growth so you would not want to prune much later than the first week in October since hard frosts that could kill new growth occasionally arrive as early as Thanksgiving.

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