Isotoma axillaris
Rock isotoma, Star flower
Also known as Laurentia axillaris
- Height × spread
- 0.5m × 0.6m
- Position
- Full sun
- Hardiness
- Mild winter to -5C (RHS H3)
- Flowers
- Summer
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
This has delightful starry flowers having five long slender, wavey and tapering petals round a small eye. The flowers are in shades of blue, white and pink. It is free flowering and covers the rather jaggy slender foliage with its blooms. The foliage has been likened to that of a thistle in its appearance, but it is of course, generally invisible. These are low growing and generally used in containers and baskets. Note: the sap of these plants is said to be a skin irritant.
- Flower colour
- Blue, Pink, White
- Foliage colour
- Green
- Variegated
- No
- Scent
- No
- Shape
- Dome
- Height
- 0.5m
- Spread
- 0.6m
- Season of interest
- Summer
- Flowers in
- Summer
- Evergreen
- Evergreen
- Garden style
- Indoors, Conservatory
- Sun or shade
- Likes full sun, tolerates part shade
- Soil type
- Chalk, Loam (normal)
- Soil pH
- All types
- Drainage
- Moisture retentive soil, Well drained soil
- Hardiness
- Mild winter to -5C (RHS H3)
- Borders & containers
- Borders and containers
- Indoor light
- full light at all times
- Indoor temperature
- 10C minimum temperature
- Hazards
- Yes, potentially harmful; Humans: Skin irritant
Spring
Spring-Autumn · Indoors
Feed with houseplant food monthly
Give the plant a balanced houseplant feed monthly while in growth.
Where food elements are listed as three numeric values on the label representing in order Nitrogen(N)-Phosphorus(P)-Potassium(K), with percentage values for each, choose one where the values are more or less equal.
Spring-Autumn · Indoors
Water regularly during growth
Water regularly while in growth.
Adopt a regime that means the plants are thoroughly watered every week so that they do not become dessicated. In hot weather watering may need to be more frequent, but less often in cool or moist conditions.
Spring - late · Outdoors
Feed with slow release fertiliser
Apply a general purpose slow release fertiliser, spreading it around the root area of the plant as it is coming into growth. (Or apply a liquid feed at regular intervals throughout the growing season.)
This is a simple way to provide a nutrient boost as a single annual procedure.
Spring-Autumn · Outdoors
Water to keep the soil moist
For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.
Without regular watering some plants never fully regain their beauty.
Winter
Winter-Spring · Indoors
Water lightly in winter
The soil should remain just moist during the cold months when the plant is not in growth. Trickle a little water onto the soil surface every couple of weeks if the soil is dry. Do nothing if it is moist.
The roots remain active in winter and benefit from small amounts of moisture so they don't become completely desiccated.
Planting & general
Compost · Planting
Loam based houseplant compost for repotting
Buy container or house plant compost that is loam based if possible (i.e. is based on John Innes compost number 2 or 3. This contains more fertiliser and is better suited to established plants.
John Innes no. 1 has the lowest level of fertiliser and is used for seedlings and young plants, so is generally used where plants will be 'potted on' after a number of weeks.
Indoor temperature · Planting
10C minimum temperature
This plant requires a minimum temperature of 10 Centigrade.
Indoor plant · Planting
Position in a sunny spot, close to window
Give this plant a position where there is as much light and sunlight as possible, within 2-3 metres of a sunny or bright window (one that is south, east, or west facing).