The 2026 theme flower for Hong Kong’s “One Person, One Flower Scheme” is Scarlet Sage (Salvia splendens), a widely cultivated ornamental plant valued for its vivid flower spikes and long blooming period. Although it is considered beginner-friendly, proper care is essential to achieve strong growth and continuous flowering throughout the season.

This guide provides a comprehensive, practical reference covering growth conditions, watering, fertilisation, repotting, pruning and problem management.

1. Understanding the Plant

Scarlet Sage is a tender perennial grown as an annual in many regions. In Hong Kong’s subtropical climate, it grows best during the cooler months (late autumn to spring), which aligns with the school programme cycle.

Key characteristics:

Upright growth habit (typically 20–60 cm tall)
Bright red tubular flowers arranged in spikes
Fast growth under suitable conditions
Moderate tolerance to heat and humidity

Healthy plants should appear:

Compact and bushy
Deep green in foliage
Producing multiple flower spikes rather than a single stem

2. Light Requirements

Light is the most critical factor influencing flowering.

Optimal conditions:

4–6 hours of direct sunlight daily
Bright, well-lit environment for the rest of the day

Suitable locations:

South- or east-facing windows
Open balconies
Outdoor school planters

Insufficient light leads to:

Leggy growth (long, weak stems)
Pale leaves
Delayed or reduced flowering

If grown indoors, the plant should be placed as close as possible to a bright window. Rotating the pot every few days helps ensure even growth.

3. Watering Practices

Scarlet Sage requires consistent but controlled watering. The goal is to maintain evenly moist soil without waterlogging.

How to water properly:

Check soil daily by touching the top 2–3 cm
Water when the surface feels dry
Apply water until it drains from the bottom

Frequency:

Typically every 2–4 days, depending on temperature and sunlight
More frequent watering may be needed in warmer, sunnier conditions

Critical principles:

Never allow the plant to sit in standing water
Ensure the pot has drainage holes
Avoid wetting leaves excessively, especially in humid conditions

Signs of watering issues:

Overwatering: yellow leaves, soft stems, root rot smell
Underwatering: drooping leaves, dry and compacted soil

4. Soil and Drainage

Proper soil structure is essential for root health.

Ideal soil composition:

General-purpose potting soil (loamy base)
Mixed with drainage material such as:
- Perlite
- Coarse sand

Characteristics of good soil:

Retains some moisture
Drains excess water quickly
Does not compact easily

Drainage requirements:

Pots must have drainage holes
A thin layer of coarse material at the bottom can improve drainage

Poor drainage is one of the most common causes of plant failure.

5. Fertilisation

Scarlet Sage benefits significantly from regular feeding, especially during its active growth phase.

When to start

Begin fertilising approximately 2–3 weeks after receiving the plant, once it has established in its container.

Types of fertiliser

Liquid fertiliser (recommended for beginners)

Balanced formula such as 10-10-10 or 20-20-20
Dilute to half the recommended strength

Apply every 10–14 days

Slow-release fertiliser

Granular form mixed into soil
Provides nutrients over time

Apply every 4–6 weeks

Nutrient focus

Nitrogen (N): promotes leaf growth
Phosphorus (P): supports root and flower development
Potassium (K): improves overall plant strength

Important precautions

Do not fertilise dry soil; water lightly beforehand
Avoid over-fertilising, which can cause:
- Leaf burn
- Excess foliage with fewer flowers

6. Repotting (Transplanting)

Repotting allows continued growth once the plant outgrows its original container.

When to repot

Roots emerge from drainage holes
Soil dries out very quickly after watering
Growth slows despite good care

Selecting a new pot

Increase diameter by 2–5 cm
Ensure adequate drainage holes
Avoid excessively large pots, which retain too much moisture

Repotting procedure

Prepare new pot with fresh soil
Water the plant lightly beforehand to reduce stress
Gently remove plant from original pot
Loosen outer roots slightly if compacted
Place into new pot at the same soil level
Fill gaps with soil and firm lightly
Water thoroughly to settle the soil

Timing considerations

Best done during early growth stage
Avoid repotting during peak flowering unless necessary

7. Pruning and Maintenance

Regular maintenance improves plant structure and encourages more blooms.

Deadheading

Remove faded flower spikes by cutting just above a leaf node.
This prevents energy from being wasted on seed production and promotes new flowers.

Pinching

In early stages, pinch off the top growth tip:

Encourages branching
Produces a fuller, bushier plant

General upkeep

Remove yellow or diseased leaves
Keep soil surface free of debris
Monitor plant shape and balance

8. Pest and Disease Management

Scarlet Sage is relatively resistant but may still encounter common issues.

Common pests

Aphids
Whiteflies

Control methods:

Rinse with water
Apply mild soap solution
Ensure good air circulation

Fungal problems

Often caused by:

Excess moisture
Poor airflow

Prevention:

Avoid overcrowding
Water at soil level
Improve ventilation

9. Encouraging Continuous Flowering

To maximise blooming:

Provide sufficient sunlight
Maintain consistent watering
Fertilise regularly but moderately
Remove old flowers promptly
Avoid stress (e.g., sudden temperature changes)

Healthy plants can produce multiple flowering cycles over several weeks.

10. Final Notes

Scarlet Sage is chosen for the scheme not only because it is easy to grow, but because it responds clearly to care. The difference between a neglected plant and a well-maintained one is immediately visible.

For students, this makes it an ideal learning tool. The plant reflects the quality of attention it receives: consistent care leads to strong growth and abundant flowers, while neglect leads to rapid decline.

With proper handling, the plant will not only survive the growing season but produce a sustained display of bright red blooms—marking the successful completion of both a horticultural task and an educational experience.

A Detailed Care Guide to 2026’s Theme Flower: Scarlet Sage (一串紅)