Mimosa. Mi-MOH-sa. It’s a tree that looks like it sounds. Tropical, exotic, with a distinctive parasol form. Mimosa possesses fine, bipinnate foliage and wispy pink flowers. Mimosa, with its susurrating final syllable, suggests a whispering softness and, on account of its downy, feathery flowers, one of its common names is silk tree (Albizia julibrissin).
The New Sunset Western Garden Book (2012 edition), considered the gardener’s bible in this part of the world, says that mimosa needs “regular water,” yet there is at least one local specimen I know of that, for many years, has seen no water other than our scant annual rainfall and yet it flourishes.
The mimosa tree I have in mind is currently in full bloom and stands majestically in the middle of Burbank Boulevard, just west of the San Diego (405) Freeway. There are no sprinklers in the vicinity and I cannot help thinking that this tree may have started as a volunteer. Volunteer or self-planted plants typically start from seeds that are either windblown or excreted by birds. Those seeds sprout in spots that are favorable to their growth and eventual development into mature plants.
Plants that grow on site from seeds are typically tougher than those ready-mades that are brought home, already rooted and flowering, from the nursery. I invite you to do an experiment this spring. Plant a six pack of marigolds in one of your planter beds and then scatter some marigold seeds around them. The marigold plants that grow from your seeds, in all likelihood, will be more robust than those that you planted from the six pack. (Note: in the nursery trade, a six pack refers to six plastic cells, connected together, that contain annual flowers.) The reason for this is that, from day one, the plants that grow in your bed from seeds have to adapt to existing soil, sun exposure, and other conditions particular to that garden spot. Plants imported from the nursery, on the other hand, which may have been grown in Oxnard or Fallbrook or some other distant location, will never feel as comfortable and at home as those that were born – that is, germinated — in your garden.
Getting back to our mimosa, it is worth noting that this tree has a unique growth habit. Generally speaking, trees with a mature height of twenty to thirty feet are not particularly fast growing. The mimosa tree, however, despite being of such moderate stature, reaches its maximum height in just a few years. Alas, the mimosa, in the manner of other leguminous trees such as acacias, mesquites, cassias, and sennas is not known for longevity. During the three decades or so of its life, however, you will enjoy its annual flower display and stylish umbrella form. Although mimosa has proven to be invasive in wetter climates, it does not pose a threat to wilderness habitats in Southern California and the Southwest. It should be noted that a cultivar with bronze foliage, known as ‘Summer Chocolate,’ is also available.
Mimosa pods produce seeds that anyone can sprout. Boil some water and pour it into a cup that contains a handful of mimosa seeds. Let the seeds stand in that water for 24 hours and then plant them in containers from which they may be transplanted into the garden as soon as they have reached a foot or so in height.
The origin of the word mimosa has nothing to do with the mimosa tree. Instead, it is derived from a small tropical species known as Mimosa pudica or sensitive plant. The uniqueness of this plant is in its leaves, which fold up when touched. It was given the name Mimosa because its foliar folding was thought to mime or mimic the movement of animals in response to stimuli. The foliage of the mimosa tree, while it does not fold in response to touch, is similar in appearance to that of Mimosa pudica.
Enter Jacaranda mimosifolia. The species name, mimosifolia, means that its foliage is mimosa-like in appearance, too. Jacaranda’s late spring bloom period –- its violet mauve flowers can presently be seen throughout Los Angeles — coincides with that of the mimosa tree. Mimosa and jacaranda trees are known to bloom more heavily that usual in times of drought. Both are native to drought frequented habitats – Western Asia for mimosa and Argentina for jacaranda – and the way they respond to drought stress is by going into survival mode, which means forming more flowers and thus more seeds than usual.
Tip of the Week: While the word honeysuckle may evince scowls from experienced gardeners, it really depends on which honeysuckle is under discussion. The familiar ‘Hall’s’ honeysuckle with the yellow and white flowers is an uncontrollable beast, while ‘Gold Flame’ honeysuckle is one of the most attractive vines available – with its pink, white, and salmon flowers — when it comes to covering a chain link fence. ‘Gold Flame’ blooms this time of the year and its moderate rate of growth means it will never become a maintenance headache.