Fremontodendron, or ‘Flannel bush’ is a cheerful shrub to grow for bright flowers across multiple seasons. Find out how to grow and care for this shrub in your garden.
Please be aware – Fremontodendron can cause a skin rash or irritation when handled, so always make sure to wear gloves, and keep out of the reach of children.
Plant Biography
BOTANICAL NAME
Fremontodendron, Fremontodendron californicum, Fremontodendron mexicanum
COMMON NAME
Flannel bush, California flannel bush, Fremontia.
NATIVE TO
Fremontodendron is native to California, and northwest Mexico.
DESCRIPTION
This evergreen shrub which grows to about six metres tall has broad, leathery, dark green leaves. It’s showy, saucer-shaped yellow flowers are each about 6cm in width.
What type of plant is it?
Flannel bush is an evergreen shrub, whilst the popular variety Fremontodendron ‘California Glory’ is semi-evergreen in the UK.
What colours do Fremontodendron come in?
All fremontodendron varieties come with deep yellow flowers, and dark green leaves. Some varieties have slightly different shades of yellow blooms, some being brighter, others slightly darker and close to amber.
When do these plants flower?
Flannel bush produce their flowers between late spring and early autumn each year.
Where to grow Fremontodendron
Fremontodendron prefers to be planted in a sheltered spot, which has access to full sun. They prefer well-drained soil, but some like Fremontodendron californicum specifically favour poor to moderately fertile soil too.
Where not to grow Fremontodendron
These plants do not grow well in overly moist, heavy soil, and will not perform best in overly shady, exposed spots.
Is this plant drought-tolerant?
Yes, flannel bush is a great drought-tolerant shrub for the garden.
How to grow Fremontodendron successfully
For success in growing a Fremontodendron, make sure you grow it in its preferred location and soil conditions. They don’t like to get too wet, so ensure the soil is well-draining. A sheltered location is best in the UK, as this plant is not fully hardy.
Do they require supports?
If growing flannel bush as a shrub, supports or stakes are not necessary. However, these shrubs are often trained to grow as a climber up walls. If choosing to do this, your shrub will need to be tied to a trellis or frame on your chosen wall.
Is it good for pollinators?
Yes, fremontodendron is a favourite amongst pollinators like butterflies and bees.
Is it good for wildlife?
Flannel bush has no other known benefits to wildlife in the UK.
How to choose the right variety for your garden
There are a few different fremontodendron varieties, but the ones best suited to UK weather conditions are Fremontodendron and Fremontodendron californicum. These are both evergreen or semi-evergreen, and generally hardy in UK winters.
How big will it get
Most varieties will reach an ultimate height of around six metres tall.
How to plant Fremontodendron
Plant your flannel bush in either late autumn, or early spring. This will give your plant the best chance at strong root development.
Prepare a hole in your chosen location about twice as wide as the rootball, but the same depth. Place the fremontodendron in the hole, making sure there is plenty of root space. Then backfill the hole, but not too tightly. Water the plant in place, and continue to lightly water until the wet winter weather sets in.
How to care for Fremontodendron
These flamboyant shrubs aren’t too fussy or high maintenance. Given they are planted in the right conditions, they should only need watering during dry periods. They prefer poor to average soil, and won’t benefit from being given additional fertiliser.
Do they spread?
No, flannel bush should not spread beyond its ultimate height of 6 metres and spread of 3 metres.
How to keep it looking good
Beyond giving this plant its preferred growing location and conditions, it should continue to perform well year round. However, keep an eye out for root rot during wet periods. Pruning occasionally will help the shrub to continue to look tidy.
Does Fremontodendron need deadheading?
You can deadhead the spent flowers, but beyond this deadheading is not necessary.
Does it need pruning, and when should they be pruned?
Yes, some pruning is beneficial to controlling the size and shape of this shrub. Pruning young flannel bushes encourages branch density. After removing faded flowers, prune long shoots, and lower branches. This is best done once all flowering has finished.
How to propagate these plants
Fremontodendron is best propagated by taking cuttings. The type can vary slightly depending on your chosen variety.
The hybrid variety Fremontodendron ‘California Glory’ is best propagated by taking semi-hardwood or ‘semi-ripe’ cuttings. This should be done in late summer to early autumn. The variety Fremontodendron californicum also propagates well by semi-ripe cuttings. However, you can also propagate the California flannel bush by greenwood cuttings in early summer.
The basic method of taking semi-ripe cuttings, involves cutting just below a leaf. This should leave you with a cutting about 10 to 15 cm in length. Place it in a bag in a cool spot until you’re ready to put up (within 12 hours).
Remove the lowest leaves and soft tips, so about four leaves remain. Dip the bottom into hormone rooting powder, and insert into a pot with cutting compost. Water your cuttings well, and store in a greenhouse, or cover pots with a plastic bag in a warm spot.
To take greenwood, or softwood cuttings of fremontodendron, take your cuttings early in the day. This is because the stems are full of water. Cut away non-flowering shoots, about 10cm in length. Cut just below a node, and remove the lower leaves. Dip the end in rooting powder, make a hole in a pot of cuttings compost, and insert the cutting. Water it in well, and cover it with a plastic bag in a warm position. Remove the bag every couple of weeks for a few minutes to aid ventilation.
What problems can Fremontodendron have?
Generally, funnel bush is pretty pest free. It is possibly susceptible to a couple of fungal diseases.
Honey fungus
Honey fungus is the most destructive disease which can impact UK gardens. It is comprised of several fungi species within the Armillaria genus, and spreads underground, killing plant roots. This then decays the dead wood.
What you will notice is during hot, dry weather, the roots will fail, and upper parts of the plant will die. The bark at the base of the plant’s stem by crack and ‘bleed’, and the plant may fail to flower. If the conditions are particularly favourable to this fungus, mushrooms may appear from the infected plant.
If your plant is affected by honey fungus, the only treatment is to destroy any infected material. It is best to destroy the material by landfill, or by burning. To stop it spreading to the rest of the garden, position underground physical barriers, which should protrude from the soil by 2-3cm. You shouldn’t plant anything in the soil you have had honey fungus in for between six months and a year. This should kill off the fungus completely.
Phytophthora root diseases
This is the second most common fungal disease you will see in UK gardens. This comes from a variety of Phytophthora species. You are unlikely to notice any overground symptoms until the root damage has become advanced.
Symptoms you will eventually notice include wilting and yellow foliage, and branch dieback, which will increasingly worsen. Below the ground, the root system will be extremely poor and rotted.
To avoid this happening, ensure the soil has plenty of effective drainage. Destroy any infected plants and replace the soil with fresh topsoil.
Varieties of Fremontodendron to have
Fremontodendron ‘California Glory’ is one of the most commonly grown varieties in the UK. This lovely variety is half hardy and a vigorous evergreen, great for consistent colour across seasons. It begins its flowering season in May, and can continue all the way through to October during favourable conditions.
Fremontodendron californicum is a similar variety from which the hybrid ‘California Glory’ was created. This one is semi-evergreen in the UK, so depending on conditions may lose its leaves in winter.
Best time of year to buy this plant
It is best to buy this from garden centres around the time you would plant it, so either late autumn or early spring.
The best garden design style for this plant
Flannel bush is a great feature of wall side borders, as it prefers sheltered conditions. It can also be trained as a climber, using a trellis or a frame for support.
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David Domoney is a Chartered Horticulturalist, Broadcaster, and Author. David has worked with a number of the UK’s leading garden retailers as a plant buyer and strategic consultant. With more than 30 years experience, in horticulture, David is as passionate about plants now as he was when he bought his first plant at a village fete.
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