Lyonothamnus

( lye - on - oh - THAM - nus )

At-A-Glance Information

This genus of evergreen trees includes just one species, Lyonothamnus floribundus, which needs full sun and moderate water to perform well in the landscape. These trees are native to the Channel Islands off the coast of Southern California and produce leaves with scalloped edges. The straight species is rarely seen in cultivation, though subspecies Lyonothamnus floribundus asplenifolius, or the Fernleaf Catalina Ironwood, is a popular landscape ornamental tree. Individual plants reach up to 20-35 feet tall and 15 feet wide at maturity, have red-brown bark that peels off in strips, and produce deep green leaves with gray undersides. Foliage emits a distinct strong, rich, spicy scent when crushed or rubbed. Flowers bloom in late spring to early summertime and are very attractive to native pollinators. They have a very light scent that can be slightly unpleasant or musty. Use these prized landscaping trees as specimens, for screening, in groves along property lines, for erosion control in sloped areas, or in habitat, wildlife, drought tolerant, or native gardens. Lyonothamnus is a member of the plant family Rosaceae. It is closely related to Prunus (Plums, Cherries, and Peaches), Malus (Apples), Pyrus (Pears), Crataegus (Hawthorn), and Rosa (Rose). and grows well in USDA hardiness zones 8-10 or Sunset growing zones 14-17 and 19-24. To find your zone, click here: Zone Map.

Caring for lyonothamnus

Lyonothamnus trees can be brittle, and should not be planted in areas of the garden where they experience high winds. They are prone to dropping large branches and require careful pruning to void snap hazards in wind storms. Also keep in mind that mature trees will continuously shed large pieces of bark, twigs, and leaves, which can clog drains and create a mess on hardscaped areas and swimming pools. These evergreen trees are fans of full sun to partial shade exposure in the landscape. They should receive at least 6-8 hours of direct sun each day, and will grow more vigorously and flower more profusely with this exposure. Ensure that soil is well-draining before planting; these trees prefer sandy to loamy soils, but can tolerate and/or adapt to a wide variety of substrates, including poor soils. They prefer soil to be slightly acidic to neutral, with a pH of between 6.0 and 7.0. These trees are great for planting in areas that have dry, rocky soils that are not overly fertile. Despite this ability, these trees should be planted in an area that has been amended with plenty of organic matter to give them a head-start on growing a strong root system. After installation, apply a thick layer of mulch around the planting area to increase soil moisture retention, suppress weed growth, and regulate soil temperatures.

Pruning these trees is simple; they do not typically require extensive prunings, but regular maintenance can keep them looking tidy and healthy. In late winter or early springtime, simply remove dead, damaged, diseased, or crossing branches to improve airflow through the canopy and shape the tree. Younger trees should be pruned up to encourage a single leader to form. These trees are also not demanding of nutrients. They can get by year after year with simple applications of organic compost to their root zone. If trees seem to be struggling, or if they are grown in particularly poor soils, they may benefit from a feeding with a balanced, slow-release fertilizer in springtime to support the season's foliage growth and flowering. Catalina Ironwood trees have an average life span of between 20 and 50 years before needing to be replaced.

Propagation

Lyonothamnus can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. To propagate your tree, follow the instructions below:

Propagating Lyonothamnus by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In late summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch greenwood portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new tree.

Propagating Lyonothamnus by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds in late summer or fall. The seed pods on Lyonothamnus plants are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Harvest as many as possible, placing them in a paper bag and then leaving them in a dry, cool, dark area.
Catalina Ironwood seeds are notoriously difficult to propagate, as there are a high percentage of hollow seeds and the ones that remain have low viability. Seeds and chaff must be rubbed vigorously over fine sieves to release them from their capsules. To test for viability, place cleaned seeds in a bowl of water. Viable seeds will sink, and the ones that float can be discarded.
Before sowing, seeds need to be pretreated. Place seeds in a bowl and pour hot (about 140 degrees Fahrenheit) water over them. Leave them for 45 minutes to soak.
In fall, water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place seeds about a quarter inch to a half-inch under the soil surface. Cover them with soil and water. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the sapling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.