Mexican Oregano Bush (or, Rosemary Mint) (poliomintha longiflora)

By Mary Cennamo, Bexar County Master Gardener

Mexican Oregano Bush has an interesting history in Texas. In the early 1930s, this dried herb was known as  Wild Mexican Sage and was found most frequently at the  state’s local Mexican markets. Sometime after the 1980s, it was no longer available at the markets but began to be sold in plant form at nurseries in Austin and elsewhere  under the name Mexican Oregano Bush or Rosemary Mint. Today, one can find this plant in most gardening centers, and it is most commonly referred to as  Mexican Oregano Bush (poliomintha longiflora). 

This herbal perennial bush originated in northeastern Mexico, the arid regions of the U.S. southwest, and in  Haiti. It is drought tolerant but needs supplemental watering during the hot summer months and when first planted in order to be established.  Mexican Oregano Bush will thrive in full sun but can tolerate afternoon shade. It prefers slightly alkaline, well-drained soil and should dry out after waterings. During the scorching summer months in San Antonio, I water mine weekly with a dripper hose; the rest of the year, the plant can easily survive on the rain we receive and does not need any supplemental watering.

This herbaceous perennial grows to about 3 feet high and just as wide if grown in full sun. The lavender/ pink flowers bloom from spring to autumn, and oftentimes, the branches become so heavy that they become prostrate with the weight of the flowers. The flowers are tubular- shaped and are an excellent source of nectar for the many bees, butterflies and hummingbirds that find their way to my garden daily to visit. The nectar produced by the flowers is critical to their survival during the summer when few other plants are flowering.

Unlike other plants, Mexican Oregano Bush has few bug pests. I never see tiny holes in the leaves as I do in my vegetable plants or my hibiscus. This bushy herbal perennial is also known to be a good deer repellent. Since the deer love to snack on my flowers and unopened blooms. which is maddening, I recently decided to plant a Mexican Oregano Bush in a pot right next to my flower garden in the hopes of deterring the deer.

Since the Mexican Oregano Bush is a tender perennial, it will typically die back in San Antonio when the temperatures drop to below 20 degrees. Fortunately, both my plants  survived the snowstorm of 2021, when we experienced consecutive days of below 20 degree weather, so it may  be more freeze tolerant than once thought. Its survival may also be due to the plant’s close location to the south side of my house. Perhaps the mulch layers that I put around my garden in May also protected them from the harsh winter weather.

Mexican Oregano Bush has many uses aside from being a beautiful plant specimen in your garden. The herb can be used in cooking—on pizza or in soups or stew—as a substitute for “regular” oregano. Mexican oregano is flavorful and spicy: you might want to cut back on the quantity you use in cooking by about half, so the taste isn’t overpowering.

The dried flowers or leaves of Mexican Oregano Bush can also be used as tea. The plant has antioxidant attributes that are beneficial to your immune system, contributing to overall physical health and well-being.

In short, consider the Mexican Oregano Bush for your south Texas garden. It is a hardy plant and once established, needs little watering except in the summer; it is deer repellent; it has a great spicy flavor and can also be used as a tea; and it is an evergreen bush during the San Antonio winters that blooms profusely with beautiful lavender/pink tubular-shaped flowers during the hottest parts of the summer.

All photos by the author.