Desert Senna

Cassia covesii or Senna covesii

This bushy perennial reproduces by seeds only, and it produces plenty of those on dried pods that I've collected over the last two years. This is a small plant and often comes in wildflower mixes, but I've never seen it for sale at a nursery, probably because it is so common. Actually, this Desert Senna plant is the only thing that came up from a package of summer wildflower seeds I broadcasted two summers ago. The stems are one to two feet high, branching from a woody base, and it flowers from March to October. Some folks find it unattractive when it is not in flower, but I don't it mind at all. It just looks good sitting there greening up a small section of my side yard.  I want more of them.

The Desert Senna is an important food source to caterpillars, which helps in the spread of native butterflies. However, I've not seen any caterpillars hanging around this lone plant, ever. In general I don't see a lot of butterflies in my landscape although I have many plants that supposedly attract butterflies, but to date, butterflies have been sparse.


Desert senna is a very common native plant of dry disturbed soil throughout Arizona, which is found along roadsides and waste places, or so they say. I really don't see a lot of it along roadsides in the areas where I travel. It also grows on rocky slopes, mesas, sandy river bottoms, washes in the deserts, and desert grassland ranges. Again, I've not seen any when I've gone into these areas.

I have hundreds of seeds from this plant that I've scattered throughout my garden, and so far, not a one has come up. If the plant is so common here in the desert, one would think I'd have a yard full by now!

Something Different, Knifeleaf Acacia

Acacia cultriformis

Acacia cultriformis, commonly called Knifeleaf Acacia, is a shrub that I added to my landscape last year. I thought it was unusual looking, and since I was looking for a small multi-trunk tree for an area that gets too much morning sun, it was a nice change from the more commonly chosen Caesalpinia mexicana (Mexican Bird of Paradise.) This Acacia will eventually grow to about 15 feet high and wide. The tough leaves are triangular and are located on the branches. As with most Acacias, it will have little yellow puff-ball flower clusters in spring. Acacia flowers have a wonderful fragrance reminiscent of honey. I located it so that it will eventually shade my large dining room window as well as provide that fragrance when the windows are open in spring.

This plant is good in USDA Zones 9-12 and requires little water once established. It loves full sun, but will take light shade. Interestingly, I've never seen any of these during the many garden tours I've attended, nor have I noticed them used in public areas. I asked the nurseryman at the place I purchased it if this was an indication that there was some problem with it, even though it matches well to our climate and conditions. He said that this shrub is not yet well known here, but he predicts that as locals see these as they grow into small trees they will become more popular, especially with folks who have smaller yards needing small desert-adapted trees.  

I'm hoping it doesn't have the negative that many other Acacias have--numerous volunteer plants from easily sprouted dropped seeds. Only time will tell!