How To Grow Mexican Heather

Cuphea hyssopifolia [KYOO-fee-uh, hiss-sop-ih-FOH-lee-uh] is a small shrub belonging to the Lythraceae family. 

It’s native to Mexico, Honduras, and Guatemala. 

flowering Mexican Heather plant (Cuphea hyssopifolia)

Cuphea hyssopifolia has several common names:

  • Mexican heather
  • False heather
  • Elfin herb

Mexican heather has been naturalized in Hawaii, where it’s often called Hawaiian heather.

It grows outdoors easily in the southern United States but requires indoor cultivation in colder regions. 

No matter where it grows, it brings a showy bloom of bright purple or lavender flowers during the summer.

Mexican Heather Care

Size and Growth

  • Mexican heather is a tropical shrub reaching a height of about 1′ to 2′ feet. 
  • It typically spreads up to 2.5′ feet and features evergreen foliage.
  • The plant has many branches and tends to develop a rounded shape. 
  • The lance-shaped leaves are evergreen, remaining on the shrub year-round.
  • The leaves are glossy green and may reach up to ¾” inch long.

Flowering and Fragrance

The trumpet-shaped Mexican heather flowers with six petals and green tubes arrive in the summer. 

The petals are lavender or purple and often attract butterflies and hummingbirds. 

The plant continues to bloom profusely until the first sign of frost.

Light and Temperature

Grow cuphea hyssopifolia in sunny locations. It can tolerate high summer heat.

The planting location for outdoor plants should receive several hours of direct sunlight in the afternoon and partial shade for part of the day. 

Mexican heather is winter hardy in USDA hardiness zones 9 to 11. 

It cannot survive freezing temperatures.

In colder regions, move the plant indoors after the flowers drop. 

Move the plant outside after the last threat of frost.

Watering and Feeding

Maintain a consistent schedule for watering Mexican heather, especially for younger plants.

Water once or twice per week, ensuring the soil remains consistently moist. 

Once established, the plant may no longer require frequent watering, and it even becomes tolerant to drought. 

Use organic fertilizer to promote fuller, healthy growth. Another option is to add liquid fertilizer with each watering throughout the spring and summer.

Soil and Transplanting

Mexican heather adapts to a variety of soils, including sandy or loamy soil. It also requires good drainage.

Add a layer of mulch around the base of the plant to increase water retention and prevent the spread of weeds around the root system. 

Mulch also protects against colder temperatures, in the event of freezing conditions during the winter. 

Grooming

Occasional grooming helps produce denser growth. If the plant starts to appear leggy, trim back the branches by a third of its current height.

Groom the plant in the spring or fall, outside of the main growing season and the winter.

Another Cuphea of interest: Cigar Plant (Cuphea ignea)

How To Propagate Cuphea Hyssopifolia

Propagate cuphea hyssopifolia from seeds, cutting, or division. 

To propagate by seed, fill 4″ inch pots with standard potting mix. 

  • Thoroughly moisten the soil and place several seeds on top.
  • Gently apply a thin layer of soil over the seeds. 
  • Place the pots in a spot receiving at least eight hours of indirect sunlight each day.
  • After the seedlings appear and are strong enough to remain upright in light wind, transplant outdoors, or to larger containers.

To propagate from cuttings, cut a four to 6″ inch branch. 

  • Remove the lower leaves from the cutting and dip the cut end in rooting hormone powder.
  • Place the tip in the soil in a 4″ inch pot. 
  • Water once or twice per week until the plant takes root. 
  • After the root system is established, transplant to larger containers or plant outdoors.

Propagating by division requires established Mexican heather plants. 

  • Carefully dig the soil around the plant to protect the roots.
  • Gently pull the plant from the ground. 
  • Place the plant on its side and use a sharp knife to divide the root ball into three or four pieces.
  • Plant each section in the ground or suitable containers. 

Cuphea Hyssopifolia Pest or Disease Problems

Mexican heather isn’t susceptible to most pests. 

The main issue to watch for is an infestation of flea beetles.

Flea beetles leave small holes in the leaves and stems, making the plant less attractive. 

The damage may eventually kill the plant.

Spider mites may also attack the plant. 

They are more likely to appear when growing Mexican heather indoors.

If either pest appears, spray the plant with water. If the infestation becomes severe start applications of Neem oil.

The water should dislodge and drown the critters.

Misting the plant daily reduces the risk of pests in the first place.

Another issue to pay attention to is the spread of the plant. 

False heather self-seeds profusely, potentially making it invasive. 

In fact, it’s considered an invasive weed in Hawaii.

Avoid growing the plant in spots where it may spread easily or remove seedlings as they appear.

Suggested Mexican Heather Uses

Use cuphea hyssopifolia for ground cover, borders, or beds. 

It also works well for edging paths or adding a container plant to patios and decks.

Recommended Reading

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