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Monday, October 31, 2011

Silk Tree (Mimosa) Should Not Be in Rock Mulch

Q. You had a timely article for me on the mimosa tree. Mine started to struggle with leaf scorch. I started deep watering and I added iron, zinc, used a 15-15-15 fertilizer. After about three weeks and I had new growth on all branches and no scorch on new growth. I should have started when the
Silk tree growing in rock mulch will always struggle
temperature increased. Why never plant them in stones? My mimosa is in an area of about 250 square feet with stones surrounding it.

A. I think you just proved my point. Mimosa is difficult to manage in a rock landscape because these rock landscapes add nothing back to the soil. Over time, the soil becomes depleted of nutrients and organic acids because nothing is added back to the soil. The organic acids from decaying organic material help these nutrients to become available to plants.

With organic mulches they are constantly decomposing and replenishing the soil with nutrients and helping to stimulate important soil microorganisms and even worms. So by adding iron, zinc and the 15-15-15 fertilizer you began to replenish those nutrients that were depleted from your soil due to the presence of the inert rock mulch.

Some plants just do not do well under rock mulch and mimosa is one of them. Your other option is to add these fertilizers every year and in some way try to compensate for having that rock mulch. Either way is fine. Your choice. But you will have to add your fertilizer combinations annually for your mimosa to do well.


  1. The mimosa tree is an extremely beautiful tree with an exotic look to it and also it can be a very unique idea to add it as wonderful plant in your garden.I really like this article.

  2. extremehort@aol.comNovember 8, 2011 at 8:36 PM

    We do have to be careful with this tree and not plant it close to our waterways such as along the Colorado River in our area. Here, from Florida.....

    Originally from China, Mimosa or Silk tree was introduced to the United States in 1745 and cultivated since the 18th century primarily for use as an ornamental. Mimosa remains a popular ornamental because of its fragrant and showy flowers. Due to its ability to grow and reproduce along roadways and disturbed areas, and its tendency to readily establish after escaping from cultivation, mimosa is considered a Category II invasive by Florida’s Exotic Pest Plant Council.

  3. Wow!Mimosa is a beautiful,fern like fragrant tree with awesome 2 inch pompom type pink flowers.These flowers look so attractive on this tree.I really like this article.

  4. Enjoy your Mimosa, Maria. It is truly a beautiful tree. We all have problems!

  5. The rock soil has no nutrition in it.Mimosa is difficult to manage in a rock landscape because these rock landscapes add nothing back to the soil