African blue basil (Ocimum kilimandscharicum × basilicum ‘ Dark Opal ‘)

Can you imagine a garden where every leaf on every plant is fragrant?
Such a garden is entirely compatible with the Mediterranean climate of Southern California. Drought-tolerant plants often have foliage containing the volatile oils that give fragrant foliage its scent.
There is an abundance of trees, shrubs and ground covers with fragrant leaves. The leaves of the plants that follow are consistently fragrant, although it is sometimes necessary to crush them in order to release their scent. Leaf fragrance also intensifies just before flowering. < Trees
Let’s start with the tallest botanical specimens with fragrant leaves, the eucalyptus trees. There are dozens of eucalyptus species, and all of them have fragrant leaves. Of course, you probably would not want to plant some of them, either because they grow too tall or they are susceptible to the lerp psyllid, an insect that has ravaged the red river gum tree (Eucalyptus camaldulensis) throughout Southern California.
My two favorite eucalyptuses are the lemon-scented gum (Eucalyptus citriodora) and Nichol’s willow-leafed peppermint gum (Eucalyptus Nicholii). In truth, the lemon-scented gum is one of the tallest eucalyptuses, reaching a height of more than 80 feet. However, the highly pungent citrus fragrance of its leaves and bark, together with an alabaster trunk, makes it worthy of consideration. Just make sure to give it plenty of sun; otherwise, it grows into a long white pole with a tuft of foliage sprouting from the top. Nichol’s peppermint gum, on the other hand, grows to only 40 feet, and has deeply furrowed red bark and a somewhat weeping growth habit in addition to its highly scented foliage.
Another peppermint tree to examine is the Australian willow myrtle (Agonis flexuosa). This is also a weeping tree with furrowed bark. It, too, does not grow taller than 40 feet, even while developing a massive trunk and thick scaffold branches. It can grow in dry or wet conditions and is suitable as a lawn tree. Subtropical trees with fragrant leaves would include all citrus species, the anise-scented avocado varieties (such as Bacon and Mexicola) as well as the camphor tree (Cinnamomum camphora). < Shrubs
My favorite aromatic shrub, which actually grows into a small tree if you have 20 or 30 years to spare, is the myrtle. For the ancients, the glistening, diamond-shaped leaves of the myrtle represented the all-seeing eyes of wisdom. If you can wait for the myrtle to mature, you will be rewarded with smooth, cinnamon-colored, otherworldly bark. Note: Do not confuse this myrtle (Myrtus communis) with the compact myrtle, (Myrtus communis Compacta), also aromatic, which is used as a 3- to 4-foot-tall hedge.
African basil is a newly available shrub that could easily pass for one of the perennial sages (Salvias), to which it is botanically related. African basil (Ocimum kilimandscharicum) cannot be found in the Sunset Western Garden Book, but you will want to grow it in your garden nevertheless. Unlike annual basil, which is a rather thirsty plant, perennial basil will grow just fine with a single weekly soaking. Perennial basil, which has culinary properties similar to those of its annual namesake, grows into a shrub several feet tall. It attracts bees and is thus a valuable asset near fruit trees or vegetable crops that require insect pollination.
The rockrose is a classic drought-tolerant plant with sweetly musk-scented foliage. The flowers of the rockrose (Cistus) have the delightful texture of crepe and may be seen in white, pink, salmon, or mauve. The shrubs grow to 3 to 5 feet in height. < Sub-shrubs and ground covers
Concerning this category of fragrant plants, which grow from several inches to a few feet tall, many pages could be written. Several common, scented herbal species are actually low-growing shrubs, including rosemary, lavender and garden sage. Ground-hugging scented plants would include prostrate rosemary, lemon-scented and woolly thyme, germander and catmint. < TIP OF THE WEEK: The only place I have seen African basil being sold is at the Studio City farmers market, on Ventura Place just north of Ventura Boulevard and east of Laurel Canyon Boulevard. It is being offered there by Annika Knoppel, who is associated with Garden of Eva Nursery. The Studio City Farmers Market is open 8 a.m. to 1 p.m. Sundays.