Santa Cruz Island Ironwood (Lyonothamnus ﬂoribundus ssp. aspleniifolius)
Lyonothamnus ﬂoribundus ssp. aspleniifolius is a mouthful to say but there is nothing edible about this tree. Lyonothamnus is endemic to the Channel Islands of California, where it grows in the chaparral and oak woodlands of the rocky coastal canyons. Lyonothamnus is a monotypic genus of trees containing the single living species Lyonothamnus ﬂoribundus, which contains the two subspecies: L. f. ssp. aspleniifolius and L. f. ssp. ﬂoribundus. The subspecies ssp. aspleniifolius is the more common species and grows wild on the following three Channel Islands: Santa Cruz Island, San Clemente Island and Santa Rosa Island; whereas, ssp. ﬂoribundus is limited to Catalina Island of the Channel Islands. Santa Cruz Island Ironwood is a somewhat shaggy tree that can grow to 35’ in ideal conditions.
A former professor from my junior college days once said, “I wouldn’t plant that scruffy dog within 100’ of my house”. Ironwood, as it is commonly called, does drop a great deal of debris from its branches in the form of dead ﬂower heads and copious amounts of dead leaves. So keep this in mind when choosing a location to plant an Ironwood, though its beauty far outshines its untidiness.
Ironwood is known to be quite drought tolerant after establishment, making it a good choice on seashore properties. Its ability to tolerate salty winds, poor soils, extended dry periods, be mostly pest free, and be slow growing are only the beginning of its attributes. By far, the most impressive feature of this tree is its foliage of lobed, compound dark green glossy leaves. From April through May it has creamy, white umbels (ﬂowers) that provide bees with a good source of native pollen. Lastly is its stunning ﬁbrous red-brown to grayish bark that sheds to reveal deep cinnamon red new bark as the tree matures.
This small tree needs some room to grow. I would suggest it has at least a 10’ by 10’ area to establish itself. I have seen them planted as a windbreak and they look ﬁne in a row. Ironwood is mostly propagated by cutting and can also be grown from seed. In the beginning, protection from deer, rabbits, and gophers may be necessary; I recommend a temporary 4’ high garden fence around the tree as well as planting inside a gopher basket. (All these items can be purchased at most hardware stores.)
It is not really necessary to use a soil amendment but probably wouldn’t hurt to do so. Adequate water in the beginning is necessary, so build a basin around the trunk large enough to handle a 5-gallon bucket of water and water weekly for the ﬁrst month to ensure quick establishment. Follow up with bi-weekly watering through the second and third months. After that, monthly watering should be ﬁne. This is just a general watering guideline so you will need to use your best judgment. By the way, you can use this water guideline on any plant. Now that I have told you all about Ironwood, I’m guessing you might want to know where to get one. Luckily Lyonothamnus ﬂoribundus ssp. aspleniifolius (Santa Cruz Island Ironwood) is readily available in the nursery trade and you should not have any problems purchasing this very rare and unusual species.
Until next month, Happy Gardening.
John Nowak and Suzette Girouard, Plant Sale co-Chairpersons.