Isodon serra (Isodon serra)

Also known as: Painted Lips Plant, 小石竹, 石竹草, 石竹

Isodon serra is characterized by its upright, woody stems and serrated leaves, which hint at its name. Its tubular, pale blue to purple flowers cluster at stem tips, attracting various pollinators. Thriving in well-drained soils under full sun exposure, isodon serra's robust growth is often linked to its preference for warm and temperate regions, suggesting a resilience to diverse growing conditions.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting

Attributes of Isodon serra

Lifespan

Perennial

Plant Type

Herb

Plant Height

1.5 m to 2 m

Spread

30-60 cm

Leaf Color

Green

Flower Size

10 cm to 20 cm

Flower Color

Purple

Images of Isodon serra

Quickly Identify Isodon serra

Isodon serra can be identified by its serrated leaf margins, tubular flowers with a violet hue, and the characteristic fragrance of its leaves when crushed. The plant often grows to form a small shrub.

Scientific Classification of Isodon serra

Phylum

Vascular plants

Class

Dicotyledons

Order

Lamiales

Family

Mint

Genus

Isodon

Species

Isodon serra

Planting and Growing of Isodon serra

Care Difficulty

Easy

Watering Schedule

Every 4 days

Sunlight Requirements

Partial sun

Sunshine Duration

4-8 hours

Ideal Temperature

65-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

6.5-7.5

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Terracotta

How to Water Isodon serra?

Isodon serra, or commonly known as the serrated isodon, requires a moderate watering approach. The soil should be kept evenly moist but never waterlogged. Watering should be done until the top 1-2 inches of soil are adequately moist, which typically requires around 250 milliliters per session.

What are the symptoms of an underwatered Isodon serra? ›

What should I do if my Isodon serra is not getting enough water? ›

What are the symptoms of an overwatered Isodon serra? ›

How to save an overwatered Isodon serra? ›

What Are the Sunlight Requirements for Isodon serra?

Sunlight Requirements: Partial sun

Duration of light: 4-6 hours daily

Isodon serra prefers partial sun, benefiting from morning sunlight and dappled afternoon shade, encouraging robust growth and vibrant flowering.

How much sunlight is best for Isodon serra? ›

How to ensure ideal light conditions? ›

Benefits of ideal lighting for Isodon serra ›

What Is the Ideal Temperature Range for Isodon serra?

Ideal Temperature: 65 ~ 75℉

For optimal growth of Isodon serra, maintaining an ambient temperature range of 65 to 75 degrees Fahrenheit is crucial. This temperature range promotes healthy photosynthesis, nutrient uptake, and overall plant vitality, thus ensuring good flowering and leaf development.

What Soil is Best for Isodon serra?

Soil type: Loam, Sandy loam

Soil PH: 6.5 ~ 7.5

Isodon serra prefers soil that drains well to prevent root rot. Well-drained soil ensures that excess water does not accumulate, thereby reducing the possibility of waterlogged conditions that can be detrimental to plant health. This plant thrives in moderately fertile soils that are rich in organic matter. The presence of nutrients in the soil supports healthy growth and robust flowering, offering a lush appearance throughout the growing season. While good drainage is critical, the soil should also be able to retain some moisture to keep the plant hydrated between waterings. Sandy loam or loam types facilitate this balance, ensuring the plant has consistent access to water without becoming oversaturated.

How to Fertilize Isodon serra?

Fertilizer type: Balanced

Isodon serra prefers moderate amounts of fertilizer, as too little can stunt growth, and too much can cause nutrient burn. A balanced fertilizer with an NPK ratio of 10-10-10 is ideal, applied at a rate of 5 grams per plant for slow-release granules or diluted in water at a ratio of 1 tablespoon per gallon.

How to Prune Isodon serra?

Pruning Time: Spring, Summer

Prune during early spring or summer when the plant is actively growing. This ensures that it has enough energy reserves to recover quickly from the cuts and can continue thriving throughout the season. Make clean cuts at a 45-degree angle, just above a node or bud to encourage new growth. Avoid cutting too close to the bud, as it may dry out, and leave about 1/4 inch above the node. To maintain a compact shape, remove about a third of the length of leggy branches, and routinely check for overgrown areas. This not only keeps the plant neat but also stimulates flowering. More About Pruning Techniques→

How to Propagate Isodon serra plant?

Propagate Time: Spring,Early summer

Harvest seeds directly from mature plants in the late summer. Ensure they are fully ripe to maximize their viability in germination. Clean and dry seeds thoroughly before storage.

Use a mixture of peat moss and sterile potting soil for seeds, ensuring good drainage. For cuttings, a mix including perlite can enhance aeration and promote root development.

Sow seeds evenly in starter trays or plant cuttings into soil. Maintain consistent moisture but avoid waterlogging, which can cause root rot. Cover trays with plastic domes to retain humidity.

More About Propagating Techniques→

How to Repot Isodon serra plant?

Repotting frequency: Every 2-3 years

Isodon serra should be repotted when you notice the roots are tightly bound or growing through the drainage holes. Spring and autumn are ideal seasons as the plant is less stressed by extremes in temperature, making it easier to adapt to a new pot.

Select a pot that is 1-2 inches larger in diameter than the current one. Preferably, use a pot made of clay or terracotta to facilitate better air flow and drainage. This size and material help regulate moisture levels, reducing risks of overwatering.

Opt for well-draining loamy soil for repotting. This soil type ensures adequate moisture retention while allowing excess water to drain away. It prevents waterlogging, thereby minimizing the risk of root rot and promoting healthy plant growth.