Polygala myrtifolia, also known as polygala or Cape milkmaid, is an evergreen shrub native to South Africa that has established itself as a favorite choice for those seeking an easy-to-maintain, colorful, and highly adaptable garden. Its spectacular flowering, hardiness, and versatility have made it a leading ornamental species for both Mediterranean gardens and temperate and tropical climates.
Characteristics and botanical description
La Polygala myrtifolia It is a perennial shrub that can reach a height of between 1,5 and 4 meters, depending on its size and growing conditions. for Growth It is quite fast, forming compact and dense masses of foliage, which makes it ideal both as a solitary specimen and in the formation of hedges or flower borders.
Sheets: Its leaves are small, narrow, oval or oblong, light to dark green, and strongly resemble those of the myrtle, giving it the epithet 'myrtifolia'. The foliage is dense and remains green year-round, adding to its ornamental value.
Flowers: One of its greatest attractions lies in its flowers, which appear in terminal clusters and range in shades from mauve to violet and deep purple, with a characteristic central keel and pale stamens. Their shape is reminiscent of butterflies, and they can appear from spring until well into autumn, and even, in mild climates, almost year-round.
Fruit: Once pollinated, it produces winged capsules containing the seeds. These capsules contribute to the plant's visual interest after flowering.
Purchase formats and ornamental uses
- Bushy growth: Grown in pots or containers, pinched and branched to maintain compact, globose growth. Ideal for borders, low hedges, and flower clusters.
- Pyramid format: Guided by a tutor to achieve attractive pyramid-shaped growth.
- Cup or high foot format: It has a thin, sturdy main stem crowned by a dense mass of leaves. It is widely used in patios or entryways to add elegance.
- Large pots or planters: Perfect for terraces and patios, where watering and exposure can be better controlled.
The polygala is extremely versatile: it can be used as a hedge to create visual barriers, as a focal plant thanks to its striking blooms, in rock gardens and slopes, or simply as a single specimen on a lawn or terrace. Its resistance to salinity makes it ideal for coastal gardens.
Ideal exposure, light and location
This species is characterized by its preference for sunny locations, where it will bloom abundantly and grow vigorously. Although it can tolerate partial shade, the quantity and quality of its flowers will decrease in the absence of direct light.
When growing indoors, it's essential to place it near large windows or in very bright spaces, ensuring at least several hours of direct light per day.
In areas with harsh winters, it is advisable to protect it from intense frost by planting it in pots so it can be moved to sheltered spaces during the colder months, or by using mulch.
Soil and transplant requirements
La Polygala myrtifolia It is not demanding in terms of soil, as long as a suitable soil is ensured. good drainage. It can grow in neutral, acidic or slightly alkaline substrates.
- Ideal soils: Light, fertile and with good organic matter content.
- Poor or dry soils: Tolerates xeriscaping and relatively arid conditions once established.
- Recommended mix: Universal soil mixed with compost or humus, and if the soil is very clayey, add up to 50% washed river sand to improve aeration and prevent compaction.
When repotting, add a layer of gravel or expanded clay to the bottom of the container or hole to ensure water drainage and prevent waterlogging, the main cause of root problems.
Irrigation and water needs
One of the advantages of the polygala is its drought resistanceHowever, to achieve more abundant blooms and a healthy appearance, it is advisable to follow certain guidelines:
- During the summer or in very hot areas: Water moderately and regularly, avoiding waterlogging. In pots, this can be done up to 2-4 times per week.
- Coldest season: Reduce watering so that the substrate remains slightly moist, but never soaked.
- Pot vs soil: Plants in containers require more attention, as their root systems are more vulnerable to lack of water.
Overwatering promotes fungal diseases, while extreme drought can reduce flowering or cause partial defoliation. A balance is essential.
Fertilization and fertilization
To maintain the intensity of the flower color and the overall health of the plant, it is advisable to fertilize during the period of maximum development (spring and summer):
- Liquid fertilizer for flowering shrubs: Every 3 weeks mixed with the irrigation water in pots.
- Slow-release fertilizer: Spread over the substrate and lightly incorporated at the beginning of the growth period.
- In garden soil: Use granular fertilizer around the base of the plant and water after applying.
In rich soils and mild climates, it can thrive even with minimal fertilizers.
Pruning and shaping the bush
The polygala does not require severe pruning, but it responds well to gentle trimming to maintain the desired shape and remove damaged branches:
- Formation pruning: To achieve a low, compact shrub, leave several main stems and trim the protruding branches. If you prefer a tree-like shape, remove the lower branches and keep a single main stem.
- Maintenance pruning: Remove dead or damaged branches in late winter or early spring. Avoid overpruning during flowering to prevent flower production.
- Pruning in pots: It is useful to control size and encourage branching.
Gentle, regular pruning maintains a vigorous and balanced plant.
Multiplication and propagation
- Seeds: They can be sown in spring in protected trays. Germination can be slow and requires constant moisture without flooding the substrate.
- Semi-woody cuttings: Obtained in late summer or autumn. They are the preferred option for ensuring specimens identical to the parent plant and root easily in sandy soil.
Propagation by cuttings is the fastest and most reliable technique in home gardening.
Main pests and diseases
La Polygala myrtifolia It stands out for its excellent resistance to pests and diseases. However, in stressful situations, it can be affected by:
- Aphids and mealybugs: They feed on the sap and can weaken the plant. The most environmentally friendly treatment is to apply potassium soap or neem oil.
- Insect larvae and leaf miners: They can cause damage to leaves and stems. Monitoring and insecticide treatment are recommended only if the attack is severe.
- Fungal diseases: Excessive moisture and poor drainage predispose to powdery mildew and rust, which manifest as white spots or brown patches on the foliage. Promoting ventilation and avoiding overwatering are essential.
In some regions, the marketing of polygala has been restricted due to its relationship with the Xylella fastidiosa, a bacterium that can affect important agricultural crops. Plants resistant to salinity They also contribute to maintaining healthy plants in coastal gardens.
Adaptability to different climates and regions
Polygala myrtifolia is highly valued for its adaptability:
- It thrives in Mediterranean and coastal regions with mild winters.
- In tropical and equatorial climates, it is essential to ensure well-drained soils and sufficient aeration to prevent diseases caused by excess moisture.
- In temperate climates it can tolerate cold, but must be protected from intense frost.
- In regions with extreme heat, regular watering is recommended during heat waves, and partial sun protection is considered during the hottest hours to prevent leaf burn.
Its resistance to salt winds makes it one of the best options for maritime gardens.
