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Plant Profile

Yellow Scrub Balm (Dicerandra christmanii)

Global Rank: G1 - Critically Imperiled
Legal Status: Federally Endangered
Family: Lamiaceae
State: FL
Nature Serve ID: 135619
Lifeform: Subshrub, Forb/herb
Date Inducted in National Collection: 04/04/1991

Description:

Dicerandra christmanii is a small fragrant shrub smelling of eucalyptus. It reaches a height of up to 1.3 feet tall. The stems are square with low ridges. Both stems and leaves, which are pitted with oil glands, have a strong mint odor. The narrowly oblong leaves are about 1 inch long, have smooth edges, and grow opposite each other. The vegetative and flowering branches are stiff as they rise from the branching woody base. The tap root is also branched with extensive, spreading, fibrous roots. Blooming in July - November, the flowers of Garrett's mint, or Garrett's scrub balm as it is sometimes called, grow in whorls around the square stem with 1 - 3 flowers per whorl. The white or cream colored flowers have purple spots and lines, are 2-lipped with rounded lobes and have sharply bent tubes. The stamens have bright yellow anthers that extend beyond the flower (FNAI 2000). The pistil is white, as well as the pollen, and the fruit is a schizocarp of four ovoid, brown, smooth nutlets. The seeds do not have mechanisms for wind dispersal and generally fall close to the plant (USFWS 1999). This species strongly resembles another endangered mint, Dicerandra frutescens. The two can be differentiated by scent, leaf size, and flower color. D. christmanii smells of menthol, has shorter leaves, brilliant yellow anthers, and cream-colored flowers that maintain their color, while D. frutescens smells minty, has deep purple to white anthers, and a cream flower that fades to white. (Huck et al. 1989)

Where is Yellow Scrub Balm (Dicerandra christmanii) located in the wild?

Habitat:

Dicerandra christmanii is found within openings in oak scrub habitat (Huck et al. 1989). It prefers open areas because it does not grow well when in shaded conditions. The species occurs on well-drained yellow sands of Astatula and Tavares soil types. Another characteristic of its habitat is a seasonal high water table of at least 1 to 2 m deep. (USFWS 1999)

Distribution:

Garrett's mint is endemic to Florida, and is only found in Highlands County at this time. Having a extremely small range, all five known populations are located between Lake Jackson and Lake Istokopg

States & Provinces:

Yellow Scrub Balm can be found in Florida

Which CPC Partners conserve Yellow Scrub Balm (Dicerandra christmanii)?

Bok Tower Gardens

Conservation Actions

Tina Stanley

05/11/2023

According to a March 2023 extract of the Florida Plant Rescue Database, Bok Tower Gardens holds 9 accessions of Dicerandra christmanii totalling approximately 48681 seeds.

09/08/2020

Archbold Biological Station (ABS) has integrated research into the conservation biology of Dicerandra christmanii with monitoring efforts. ABS is investigating the breeding system, pollinators, demographic patterns, and genetic variability. (USFWS 1999).

09/08/2020

09/08/2020

Nature Serve Biotics

05/02/2017

Endemic to central Florida. The Florida Natural Areas Inventory's database contains 7 occurrence records. All occurrences are in a very narrow range in Highlands County, Florida. The species' habitat is rapidly decreasing in size and quality due to heavy development.

S.K. Maddox

01/01/2010

Loss of habitat due to urbanization and agriculture. Suppression of fire which limits open areas. Erosion due to off-road vehicular traffic, and dumping of trash. Exotic pest plant invasion. (USFWS 1999)

S.K. Maddox

01/01/2010

There are 5 populations of Garrett's mint in Highlands County, none of which are protected. (USFWS 1999)

S.K. Maddox

01/01/2010

S.K. Maddox

01/01/2010

There has been no research done on the response of D. christmanii to management practices. This species is, however, very similar to D. frutescens, and is likely to respond in a similar manner. Periodic fire appears to benefit D. frutescens. Though growth is vigorous in areas that have burned, it is not evident that the frequency of fire is as important than the fact that the area had burned in the past. Based on the reaction of the scrub mint, Garrett's mint should require a burning or alternative disturbance regime to maintain the quality of its habitat. Efforts should also be made to protect the sites from trash dumping and foot and vehicle traffic that cause erosion. D. christmanii is adversely affected by trampling (USFWS 1999).

S.K. Maddox

01/01/2010

Conduct surveys for additional populations. Maintain distribution of known populations and suitable habitat in GIS database. Protect and enhance existing populations, including ex situ collection. Continue research online history characteristics. Monitor existing populations of D. christmanii. (USFWS 1999).

S.K. Maddox

01/01/2010

Conduct research on seed storage. Conduct further research on propagation methods. Provide educational materials for the public. (USFWS 1999).