Camptotheca acuminata
Commonly known as the "Chinese Tree of Joy", this native of China makes an attractive ornamental in the container garden.  It has 8 inch, bright green, ovoid leaves and attractive seed pods.  It is a rapid grower and will be hardy in Central Austin, but fears of weak growth and possible winter kill in extreme cold prevent it from being a good addition to the landscape.  It is a member of the Nyssaceae family.  The most fascinating thing about Camptotheca acuminata is that extraction of the compound camptothecin from its leaves serves as the starting point for synthesis for two commercial anti-cancer products, iriedesar  (Camptosar from Pharmacia-Upjohn) and topotecan (Hycamtin-R from Smith Kline Beecham).   These two medications work by inhibiting the action of Topoisomerase I, an enzyme essential to the maintenance of DNA structure.

Vitex agnus-castus
A member of the Verbenaceae family, this beautiful tree is found planted in landscapes in the Austin area.  It has deep green palmate leaves with wonderful spikes of blue flowers and a subtle, but pleasing scent to its foliage.  A white flowered form is also occasionally seen.  One common name for this tree is "Chaste tree" and another is "Monk's pepper", both names are historical, referring to the use of vitex to adjust hormone levels in men and women.  Modern herbalists use parts of the tree to treat various complaints of women.

Pimenta dioica
The allspice tree is a native of Central and South American tropical regions and will not be hardy in Austin winters, but it makes a very attractive container plant with glossy green, elongated leaves.  It is an evergreen member of the Myrtaceae family.  New to the garden this year, it is unknown if it will produce allspice berries when container grown, but the leaves are delicious in their own right.  Simmer apples, sweet onion, a bit of water and an allspice leaf to make a tasty sauce for pork or squash dishes.

Laurus nobilis
Don't be fooled by local groceries selling "California Bay", Umbellularia californica, as a substitute for true bay.  Only Laurus nobilis has the wonderful flavor that recipes call for.  "California Bay" has a camphor overtone that will ruin many dishes.  Fortunately, Austinites don't have to rely on groceries for bay, it is easily grown here and is hardy although our worst winters may kill it back to the ground.  It is difficult to propagate and so will be slightly higher priced than many of the herb plants found in our nurseries, but it is well worth the extra pennies.  It is susceptible to scale so watch it carefully for small patches, usually oval, of brown along the stems and leaves and rub these scale insects off if they appear.

Ginkgo biloba
The ginkgo makes a lovely small tree for the Austin area.  It is slow growing and may even be maintained in a large container for a number of years.  The fall show of golden leaves is breathtaking and collecting a bowl of the fallen leaves is like finding a treasure chest in one's own backyard.  Herbally, Ginkgo biloba is much touted for improving memory.  Scientific studies have had varied results, but if one chooses to use a ginkgo food supplement it is important to consult a doctor or pharmacist if taking a blood thinner such as aspirin or warfarin, there is the potential for a negative drug interaction.  Evolutionarily, ginkgo, also called maidenhair tree, is an interesting plant.  It is a gymnosperm, meaning that its seeds lack a protective covering.  Other gymnosperms are conifers, whose naked seeds are held in cone structures (an example are pine cones) and cycads.  Gymnosperms are more primitive plants than angiosperms whose seeds have protective covers.  All the other herbal trees discussed on this month's page are angiosperms as are most of your other favorite herbs.  The male and female flowers of ginkgos are born on separate plants, many people complain about the unpleasant odor of the fruits, if this is a concern be sure to ask for a male tree.

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