Frequently Asked Questions & Advice

The best way for us to advise on your bonsai tree is if you can bring it into the Nursery. If you are unable to do this please send an email with pictures to [email protected]. If we can't see the tree it is very difficult to offer advise.

Keeping a bonsai is quite a time consuming pastime, and you should be prepared to water them on a regular basis if you want to keep your trees alive. 
Glossary of Terms 
Deciduous - means a plant that sheds its leaves every year.
Evergreen - means a plant that retains its leaves all year round. 
Semi-evergreen or semi-deciduous - is a term that describes a plant that will loose foilage for a short period when old leaves are shed and new growth is starting.

Q: What is the best tree to start with?
Indoors - The Chinese Elm and Ficus are the most straight forward to look after.
Q: Which is easier an outdoor or an indoor bonsai?
Indoor bonsai are more difficult to keep than outdoor bonsai, but if you are used to keeping houseplants you should be successful with indoor ones. Indoor bonsai are difficult because growing them in a room is an unnatural environment in their native habitat, they would grow outdoors. However, for someone starting out in bonsai the benefit of having one indoors is that you can keep an eye on it at all times.
Q: What is the best way to keep an indoor bonsai?
All plants require air, sunlight and water for healthy growth. Keep your bonsai on a window sill where they get maximum light, and make sure the soil is moist at all times. Never let the soil dry out. Do not leave it above any heat sources (i.e.central heating).
Q: Why is outdoor bonsai easier?
Trees live outdoors and when you grow them in their natural environment they stand a better chance of survival.
Q: Where should I put my Bonsai tree in terms of light? Near a window?
Indoor bonsai need maximum light in order to grow well. So the window sill is the best place to keep them (but if possible not above a radiator). Most indoor bonsai prefer a cool room.
Q: Why does my indoor bonsai need sunlight?
Indoor bonsai don't get the same intensity of light that they get when they are outside. Trees won't die immediately when light intensity is too low, but growth will decrease, eventually weakening the plant. Therefore ensure you place your bonsai in a sunny, south facing window (if possible)
Q: How much should I water my Bonsai?
How much water your bonsai needs isn't an exact science you will need to observe your trees individually. The following is a guide. 
Indoor bonsai
should be watered when needed, requiring more water during the growing season and less during the dormant period in autumn. Keep the soil damp at all times but not soaking wet. Forgetting to water indoor bonsai is the single most common cause of death of indoor bonsai. Frequency of watering will depend on the warmth and humidity of the room.
Outdoor bonsai You should begin to water outdoor bonsai in the spring when they start growing. Continue to water throughout the growing season, which in temperate areas is from early to mid-spring until early to mid-autumn. Moist air and rain are usually sufficient in winter, but you should water if there has been no rain for several days. 
Q: What’s the best temperature? Humidity?
Most indoor bonsai prefer a cool environment and as much humidity as possible. The Ficus however need slightly higher temperatures (12-20C is best)
Q: I'm not sure if my tree is still alive, how can I tell?
A simple scratch test will give you an indication of whether your bonsai is still alive or not. Scratch the bark on the trunk and if its green underneath it suggests signs of life, if it's brown it may be past saving.
Q: How do I prune my bonsai?
If you want to keep your bonsai small and neat don’t let the shoots grow too long. Regular pruning with scissors will keep the bonsai in good shape. A deciduous tree usually needs to be pruned twice a year. Evergreen bonsai do not require trimming as often, because they are usually less vigorous.
Q: How often should the roots be cut?
Obviously this depends on the tree, but generally every two or three years when the roots have filled the pot. Remove some of the tangled mass of roots and add fresh compost.
Q: When is the best time to repot my bonsai?
Repotting work normally needs to be done during the early spring (February & March); when the tree is still in dormancy. This way the somewhat damaging effect of repotting on a tree is reduced to a minimum, as the tree does not yet have to sustain a full-grown foliage. Repotting in early spring will also ensure that damage done to the root system will be repaired soon, as soon as the tree starts growing.
Q: How often should I repot my bonsai?
Frequency of repotting depends on how vigorous the species is (check individual plants), the warmth of the climate, size of the pot and the trees age. To check your bonsai carefully remove from the pot, if the roots are circling the root system then it’s time to repot. When re-potting bonsai, the recommended increase in pot size is no more than 1/2” (12.5mm) to 1” (25m) around the root ball. The reason for this is because a larger pot with a larger area of soil without roots in will encourage water to sour. When roots eventually reach this soil they suck up sour water which can cause stress to the tree.
Q: How often should I feed my Bonsai Tree?
With most bonsai, fertiliser should be applied only during the growing season (around March to September). If plants are given nutrients when are not growing, the fertiliser will be wasted or it will encourage growth at the wrong time of year and cause stress to the tree.
Q: Do they suffer from pests and disease?
Like all plants, bonsai are susceptible to pests and disease. If you see pests, you can get rid of them by jetting them off with a hose or use insecticide.
Q: What is a bonsai, as opposed to a tree? Are there different types of bonsai?
Bonsai is simply a tree or shrub which has been specially shaped to make it resemble a full grown tree that you would find in nature. Bonsai can be made from any plant material. You can have either Indoor or n the type of plant material that has been used to create them. So if you create a bonsai from temperate climate plants, these should be grown outdoors. If you use tropical or sub-tropical plants (the type used for house plants), then these bonsai are suitable for Indoors.
Q. Some of the leaves on my Chinese Elm are turning yellow and falling off, why is this?
The Elm is a deciduous tree and in Autumn/Winter the leaf colour will change and they will lose some if not all their leaves. All Indoor trees benefit from a spell outdoors, so if you can give your tree a spell outdoors it will benefit it greatly.The Elm can in fact be grown as an Indoor or as an Outdoor bonsai, so they are very hardy.

At Herons we water our Indoor bonsai with a hose pipe, so they not only get watered properly but also get washed at the same time.
In their natural habitat, trees get rain. So drenching the bonsai with a garden hose replicates rain. So if you can wash your Elm with a garden hose from time to time then that will benefit the tree.The alternative would be to hose it down with a tepid shower.
Q. Some of the leaves on my Chinese Elm have developed red spots on them, why is this?
It is possible that the Elm has a fungal infection. To treat you need to prune off/ remove all the effected leaves and burn them. Then treat the tree with a fungicide. 
Q. My Chinese Elm has been loosing its leaves for the past 4 or 5 months how do I tell if it's still alive?
The Elm likes to be kept in a cool room or even outside. It may have become too dry. We find that most Elms are killed by not watering correctly. The best thing to do is keep it outside and drench it thouroughly and ensure that the soil is never aloud to dry out. 

To tell if the bonsai is still alive you can scratch the bark with a finger nail and if its green underneath then there is still life.
Q. Is my Chinese Elm infested with Red Spider mite or another insect? Little tiny creatures and what looked like strings of webs.  The tree was also losing its leaves, what should I do?
Without a picture of what the pests look like, it is a bit difficult to advise. However, if it is Red spider mite or other insect pests - then you can either keep jetting off the insects with a jet of water from a hose pipe or spray with an insecticide.
Keeping the tree outdoors will also help reduce the incidence of insect pests. The Elm is a very hardy tree and can withstand very cold temperatures, so a spell outdoors will not hurt the tree. In fact the tree will benefit from being outdoors.
Q. How do I treat Mealy Bug?
Usually these bugs are treated with a pesticide (folliowing the instructions carefully), you can repeat a couple of times if necessary. Another helpful method is to take the tree outside and blast with a ose (remembers to spray the underside), you can also brush the area with soapy water (feel free to send us a photo to [email protected])
Q. How do I treat White Fly?
White Fly are common sap-feeding insects and they excrete a sticky substance (another way of telling if you have white fly is checking the foliage to see if it's sticky).
Like with the Mealy Bug they are usually treated with a pesticide (a local garden centre will usually be able to suggest something, you may need to treat more than once). You can also take the plant outside and blast with a hose (but still treat with a pesticide).
Q. I have a Dawn Redwood and Larch forest. What's the best way to look after them?
The Dawn Redwood is a hardy and vigourous tree. At Herons we do't protect ours at all during the winter, so they stay in the open at all times. If you wish, you can put yours in a cold frame, but its not necesary. Dawn Redwood love water so there's not chance of over watering them. 
Q. I have a Japanese White Pine and a Maple Bonsai, what should I do to protect them from frost and cold weather?
You can bring the tree into an unheated greenhouse that is enough protection from prolonged periods of cold. You will need to keep them damp as they won't get water from anywhere else.
Q. How do I protect my bonsai in freezing weather?
In an unheated greenhouse if you have one. However, if you don’t have a greenhouse you can do one of the following. Wrap the pot in bubble wrap (bubbles on the inside, closest to the pot) you can tape it or tie it, depending on what you have to hand, this will insulate the roots and prevent them from freezing. Or you could bury your pot (not tree) in sand which will also help insulate the roots. You may need to unwrap the tree to water if the freezing temperatures persist.
Q. The needles on my White Pine are turning brown, why is this?
The needles on White Pines can start to yellow around the end of September. This is the old needles and doesn't mean there is anything wrong with the tree. They can be easily removed and are nothing to worry about. We have a video turorial on cleaning pine needles here​