How to Care for Cuphea Hyssopifolia (Mexican Heather)

Cuphea Hyssopifolia plants are also known as the False Heather, Elfin herb, and Mexican Heather, native to Mexico, Honduras, and Guatemala and well known for their bright purple flowers. The Mexican Heather plants are summer bloomers, this means you will be able to see their flowers even after the spring ends. They are grown as indoor ornamental plants and ground cover to create a beautiful landscape.

The Mexican Heather plants have beautiful lavenders like flowers and dark green leaves. The plants can reach up to 3 feet in height and can cover 2.5 feet wide. The stem grows a large number of branches. These branches surround the stem and are covered with a large number of leaves and flowers during the bloom season.

The Mexican Heather plants grow very well in the Southern Parts of the United States, as well as other areas where the temperatures are hot. They do not like the cold and need protection if they are planted in the colder areas, you can keep them indoors to protect them from cold and frost. They are evergreen and retain their leaves all year long, but in cold areas, they sometimes shed a few leaves but still retain a large number of leaves and maintain their green appearance.

The flowers of the Mexican Heather are trumpet-like in shape, in summer they grow green tubers that carry six petals, all wrapped in the shape of a trumpet. The petals of the flowers have a purple color. The Mexican Heather plants keep flowering till the arrival of winter. Their flowers attract hummingbirds and insects that help them pollinate.

Growing Conditions and Requirements

The Mexican Heather plants are easy to grow in their natural environments and where the temperatures are moderately hot and they can receive an abundance of sunlight. But in the cold region, they need a little extra care, you must keep them indoors during the winter in cold areas to protect them from the frost and extreme cold.

They grow very well in many different soils but they show faster growth in a nutrient-rich slightly sandy and well-draining soil. If the soil you have is not good or lacks the required nutrients, you can add fertilizers to compensate for this. In indoor environments, keep them in a bright place so they can receive enough light.

Below are the details about the growing conditions and requirements:

Water Requirements

The Mexican Heather plants require a consistent water supply. They are small plants and also have small roots that cannot obtain water from the deep soil if they are grown in the ground, that is why consistent and frequent watering will help them grow properly. Another reason for consistent and frequent watering is that they are mostly grown in the hot and dry areas.

Below are the proper watering recommendations based on the different scenarios:

●     Watering starts as soon as you sow the seeds or plant the Mexican Heather in the soil. Right after the plantation, provide them some water, this will help the seeds sprout. After that, keep watering them and don’t let the soil dry. The moisture in the soil helps the seeds to sprout. 

●     After the seeds sprout and seedlings appear above the ground, you can give them water once every day in the hot areas. The early morning is the best time to water your plants. Keep following this daily watering routine for almost 2 months after the plantation.

●     Once the plant is two or three months of age, it can now access the water from a small depth of soil, now you can increase the amount of water you were giving to your plants and decrease the frequency of watering. Now, you only need to water them once every second day.

●     Keep watering them once every second day, unless the winter arrives or the plant reaches a height of almost 1 foot. In winter, increase the amount of water per watering but decrease the frequency of watering to once every 5th or 6th day.

●     As the plant reaches a mature age and height, you can increase the amount of water, and reduce the frequency of watering. In the summer you can water them once every 3rd or 4th day while in the winter, give them water once every 5th or 6th day.

The plants in the landscapes and outdoors have a different watering need, you can water them based on the soil test, check the soil for the moisture if the upper layer of the soil is dry, and provide them with water. Do not let the soil completely dry otherwise, the plants will not grow properly and some might even die due to drought situations.

Lighting Requirements

The Mexican Heather plants love growing under the sun. in their natural habitat, they receive plenty of sunlight all year round. If you want your plants to show faster and better growth, you must plant them in a way that they receive sunlight for several hours each day.

The outdoor plants that are planted in the landscape or ground covers, they receive plenty of sunlight, but indoor plants are mostly under the shade that is why they show slow growth. You must keep them in a place where they receive a sufficient amount of direct or indirect sunlight.

If the Mexican Heather plants do not receive proper direct or indirect light, they start to show abnormal growth. Apart from the abnormal growth, they also attract more pests and diseases, and chances of the death of the plant increase.

Temperature Requirements

As you know that Mexican Heather plants are native to the hot regions, they like to be grown in moderately hot environments. You can also grow them in cold and extremely hot areas, but you will have to protect them from the adverse effects of the seasons and climate. Keeping them indoors is the best way to protect them and grow them in the cold area.

They cannot survive the cold and frost and need protection during the winter. They are evergreen and hardy in the USDA zones from 9 to 11. They like to when the temperature is between 10 C to 25 C. If the temperatures are higher than this, you will have to water them more frequently to protect them from the drought that is caused due to heat.

Soil Requirements

The Mexican Heather plants can grow in a variety of soil, including clay, sandy, and loam. They can also grow in the slightly acidic to slightly alkaline and neutral soil as well. A nutrient-rich soil that can allow the excess water to quickly move out (well-draining) is the best soil for Mexican Heather plants.

Adding layers of cocopeat, mulch, compost, plant fertilizer, pumice, perlite, and sand will help you create a balanced potting soil for your Mexican Heather plants. All these materials make the soil well-draining, but adding a layer of mulch helps the soil retain the moisture for some time so that the soil will not become quickly dry after watering.

Adding fertilizer in the potting soil helps the seeds sprout quickly and supports the growth of young seedlings. Compost does the same but nutrients in the compost release slowly and keeps providing the required nutrients to your plants for the long term. The soil must not contain the spores of any fungi or remains of any type of weeds etc., otherwise, the plant’s growth and health are disturbed.

Fertilizer Requirements

Fertilizers are very important for the long term and faster growth of your Mexican Heather plants. These fertilizers provide your plants with all the required nutrients that it needs. As you know that soil only contains a limited amount of the nutrients that are required by the plant, and once the plant starts growing, it extracts and consumes all these nutrients. This creates a deficiency of nutrients in the soil, this deficiency can lead to abnormal growth, flowers and leaf death and fall.

Apart from these, the growth of the plant can also halt in some cases, to prevent this, it is important to keep feeding fertilizers to your Mexican Heather plants regularly. The most efficient way of fertilizing the plant is by testing the soil for nutrients deficiency and only using the specific fertilizers to overcome this deficiency.

All you need to do is to take a soil sample and test it, after that you can use the recommended fertilizers to treat the deficiency of that specific nutrient. But if you do not have a soil test, you will have to use a general-purpose plant fertilizer that contains all the required nutrients for your plant.

How to fertilize the Mexican Heather?

There are three methods to fertilize your Mexican heather plants:

●     The first method is used to fertilize the soil before the plantation or sowing the seeds. In this method, you need to take the required amount of required plant fertilizer and then mix it with the soil, after that provide some water so that fertilizer dissolves and becomes a part of the soil. After that your soil is ready and you can plant the seeds or sapling. This method helps the initial stage growth of the Mexican Heather plants.

●     The second method involves spreading the fertilizer around the stems of the plant, this method can be used once the plant has gained almost one-foot height. You need to take the required amount of required fertilizer and then carefully spread it in the potting soil around the stem. You can also use this method for outdoor plants as well. This method is mostly used if the fertilizers are not in liquid form.

●     The third method is used for liquid fertilizers. You need to take a required amount of fertilizer and then mix it with the recommended amount of fertilizer and provide this mixture to your plant when watering. You can feed this mixture to your plants once every 15 days.

Always use the fertilizers according to the guidelines and recommendations that are provided with the fertilizer for better results.

Pruning Requirements

The Mexican Heather plants are evergreen and they retain their foliage all year long. Their branches also keep growing and covering more space. To give them proper shape and maintain their size, pruning is important. It helps boost the growth rate of the plant and also encourages the growth of new leaves, flowers, and branches.

The best time to prune the Mexican Heather plants is after before the spring. All you need to do is to look for the diseased parts or irregular parts and start cutting them. Do not cut the central stem or branches from their core. Just cut the irregular tips of the branches and leave them.

Prune them once every year, this will help you maintain the look of your plant and will also help your plant grow properly. This will also help you prevent the attacks of different pests and fungi.

Repotting Requirements

The Mexican Heather plants are a fast-growing species, and they need repotting every year. They quickly outgrow the pots unless they reach their mature size and age. Repotting helps the growth of the plant and promotes growth as well. You can re-pot them before the spring.

Choose a bigger pot, add some soil in the pot and uproot the plant from the pot and transfer it.  After that, fill the pot with the soil and provide it water. Keep them in a bright place where they can receive direct or indirect sunlight.

Pests and Problems

The Mexican Heather plant is not susceptible to most of the pests, only flea beetles and spider mites attack the plants. Below are the details about how to prevent the attacks and kill the pests if the attack happens.

Flea Beetles:

Flea Beetles are a serious problem for the Mexican Heather plants, as they start eating the parts of the plant. They mostly eat the green parts like leaves and terminal branches and leave the holes in them. The severe attack can result in the death of the plant as well. Protect your plants and keep looking for the signs of an early attack and if you see any leaves with holes take preventive measures. Neem oil, water spray, and chemical sprays to kill them are the only options to control the spread.

Spider Mites:

Spider Mites mostly attack the indoor plants are the plants that are grown in damp places. They spread very quickly, so keep looking for the signs of an attack. If you see them on your plant, use the water spray to dislodge the foliage and then use neem oil on the plants to prevent further attack. If this does not help, use the chemical spray to kill them.

How to Propagate?

There are three ways to propagate the Mexican Heather plants, you can use the cuttings from the stem to grow the new Mexican Heather plants. You need a sterile knife, with a sharp blade to make the perfect cutting. Always choose a mature plant to take cuttings from. Keep these cuttings in the rooting hormones. Once the roots start to appear, transfer them to pots or ground.

The process division involves digging the soil and uprooting the mature plant and then dividing the root ball into two parts. After that, each part of the root ball is planted in a different pot or place in the soil. Provide them water and keep them in a bright place.

Growing from the seeds:

You can also propagate the Mexican Heather plants from the seeds, all you need to do is to fill a pot with the required soil and take some healthy seeds. Sow these seeds in the soil and provide them some water. Keep watering them daily and do not let the soil completely dry. Moisture in the soil will help the seeds sprout quickly.

Once the seedlings appear above the ground, keep watering them, and caring for them. Once they are big enough to be transferred into the new pot, repot them and keep them in a bright place.

Frequently Asked Question:

Question: Are Mexican Heather plants perennial or annual?

Answer: Mexican Heather plants in the USDA hardiness zone from 9 to 11 (slightly warm areas) are evergreen perennials. They retain their foliage and all year long even during the winter as well. But in the USDA hardiness zones below 8, they grow as annual plants, this is because the winter in these areas is harshly cold and the plants die during the winter. To grow them in these areas, you must keep them indoors and provide them protection from extreme cold.

Question: How to prune Mexican Heather plants?

Answer: Mexican Heather plants grow a lot of branches that are covered with the leaves, instead of an upward growth they tend to spread and cover more space. To prevent this and regulate their growth, you need to prune them. Pruning is mostly done before spring. You need to cut the irregular or large branches, cut out the dead leaves and terminal parts. Also, cut off any diseased parts as well. After pruning them, give them some water and leave them in a bright place.

Question: How to propagate the Mexican Heather plant?

Answer: There are three different methods to propagate the Mexican Heather plants. These methods include cutting, division, and sowing the seeds. You can easily propagate them by taking cuttings from the mature stem and keeping them in a rooting hormone, once the roots appear, you can transfer them to the pot. The division method involves uprooting the plant from the soil and dividing the root bulbs and planting them into different pots or soil. The last method involves taking the healthy Mexican Heather seeds and sowing them into nutrient-rich, moist soil.

Question: Why is my Mexican Heather dying?

Answer: There can be several reasons for the death of the Mexican Heather. The most common cause of their death is extreme winter and frost. If they are kept outdoors during the winter, they will lose all the leaves and then die. Apart from this root rot, spider mites attack flea beetle attack and can also kill the plant. But if you do not see any signs of the pest attack and yet the plant is dying, you can change the watering, fertilization schedules. If this is not helping, look for the signs of leaf scorch attacks.