Bonsai Grewia, Ref. 8079

Grewia (Grewia malafolia) is a fast-growing tropical shrub/tree that is extremely popular with bonsai masters
- branches very well
- tolerates heavy pruning very well
- thickens quickly
- has small leaves (or easily reduced)
- blooms beautifully (purple-pink flowers)
- ideal for indoor cultivation
- forgiving of mistakes, ideal for learning the art of bonsai
- deciduous or semi-deciduous tree (depending on conditions)

Age: 8 years
Height: 13 cm

Lighting
- Requires 5–7 hours of bright light
- Morning or afternoon sun
- South/southeast window
In winter, a 10–12 phytolamp is required (see here)
Not enough light:
- Long internodes
- Large leaves
- Poor flowering

Temperature

Temperature and wintering
Spring-summer: +20...+30°C
Autumn: +14...+22°C
Winter: +10...+15°C
Can overwinter at +18°C, but growth will be weaker.
Does not tolerate frost or cold drafts.
A sensor is needed to monitor air humidity and temperature (see here).

Watering
- The soil should dry out slightly (1-2 cm) between waterings.
- Water generously.
Summer: 2-4 times a week
In winter: once every 7–10 days
Does not like stagnant water or complete drying out
Use a watering indicator to monitor (see here)

Air humidity
- prefers moderate humidity
- responds well to spraying in summer
- do not keep near a radiator in winter

Soil
40% akadama
30% pumice
20% lava (drainage)
10% organic matter
(see here)

Transplanting
- young plants every 1–2 years
- mature plants every 2–3 years
The best time is spring, at the beginning of active growth.
- Shorten the roots by 30–40%.
- Form a flat root system.
After transplanting: partial shade for 10–14 days, no fertilizer for 3–4 weeks.

Pruning
Structural: radical pruning is possible in early spring
Supportive: throughout the growing season, prune to 2–3 leaves
The more often you prune, the smaller the leaves will be.

Wire and bends
Apply wire to young branches, check every 2 weeks
The bark is thin - marks remain quickly
Alternative: pruning instead of wire. The cut is made above the bud, directed outward, in the desired direction of the branch. The process can take years.

Leaf reduction
Achieved by:
- bright light;
- frequent pinching;
- root restriction;
- regular pruning;
- complete defoliation (only for strong, mature plants)

Fertilizers
During the growth period: balanced (see here)
In autumn: less nitrogen
In winter: do not fertilize

Flowering
- blooms profusely, but flowering weakens the plant's growth
Recommendation: leave only some of the flowers

Diseases and pests
- aphids
- spider mites
- whiteflies

Prevention:
- light
- good drainage
- ventilation
- neem oil preparations (see here)

Mistakes:
- lack of light
- infrequent pruning
- warm and dark wintering
- heavy soil
- neglected shaping
- less watering