White Spruce (picea glauca)

Profile: The white spruce is native to the northern temperate and boreal forests of North America. The spruce had many uses from timber to Christmas trees in areas such as Alaska and southern Canada. The spruce is relatively new to bonsai when compared with other bonsai cultivars. The spruce isn't the first choice for many bonsai enthusiasts due to its difficulty to shape and style. Despite this, the spruce is still grown as a bonsai because of its beautiful appearance. Its dense light blue/green needle clusters complement its dark trunk. Below are some important care points for the white spruce.

Tree Position: Keep this bonsai outside in a sheltered position and protected from strong winds. It may be displayed inside for up to 3 days at a time. When placed outside, place the bonsai where it will receive full sun. During mid-summer, on very hot days, keep this tree in part shade.  

Watering: Spruces like more moisture more than their conifer siblings so they will enjoy a daily misting after a hot day. You must be careful not to overwater this conifer bonsai though, water only when required. Ensure that the soil is always damp but not soaking wet. How often you water your bonsai will depend on the weather and how deep your bonsai pot is. Use your finger to check how damp the soil is before watering. If it feels a little dry, then go ahead and water.  As a general rule, water every day when it's hot, and water twice a week in colder winter months. Try not to follow a schedule when watering though, instead, check the soil to see if it is wet or dry. Wait a minute or two after watering, then water again. In Japanese bonsai culture they have a saying for this; 'For bonsai, it rains two times'.

Fertilizing: Feed your Spruce fortnightly from Spring through to mid Autumn with a liquid fertilizer that has a balanced N.P.K ratio. Always follow the directions on the fertilizer packet, and water the bonsai thoroughly before feeding to avoid root burn. Don't feed your bonsai during winter as the soil temperature isn't high enough to trigger the bonsai's response to uptake nutrients. Do not fertilize if the tree is weak or diseased. Lastly, do not fertilize newly re-potted trees for at least a few weeks.

Re-potting: Re-pot this tree every two years from early spring to mid-spring. Repot just before the buds begin to break. The soil you use should be a well-drained soil. A basic mix consists of 2 parts Dalton's coarse pumice and 1 part Dalton's potting mix. Ideally, you should use a 2 mm sieve to get most of the fine particles out. You can trim up to one-third of the roots before your bonsai goes back into the bonsai pot. Secure the tree to the pot with wire through the drainage holes. Leave a small amount of the old soil on the roots when re-potting conifers. Place the bonsai in a sheltered and slightly shaded spot for a week or two after repotting. At this crucial stage, we want to shelter the bonsai from the hot sun, heavy rain, frost, snow, and wind. Lastly, be careful to not overwater your bonsai after repotting. 

Trimming: Without any intervention, there will just be one flush of growth for the year. The growth will come from buds at the tips of the branches and closer towards the trunk if you're lucky!  You will need to perform trimming on the spruce twice a year. Once in spring after the first flush of growth. And again after the second flush of growth in late Summer to Autumn.

Spring trimming- Allow the fresh green shoots to extend 1" - 2" then prune back the new shoots by half. Cut more off the very top (apical branches) than the lower branches. Do not prune back new growth on weak branches. If you let the new shoots grow too far then back budding may be limited. 2 weeks later, more shoots will appear from where you have cut back. You should have dense growth and may even have buds growing further down the branch. No more spring pruning needs to be done until Summer (unless certain branches are growing a lot faster than others)

Late Summer to Autumn trimming - Pluck old needles from last year, or two-year-old needles up to a bud. Pluck the needles off with your fingers. This makes wiring easier and looks tidier. Don't pluck needles from non-vigorous branches. To make a dense foliage pad and to bring growth closer to the trunk you can prune back this year's growth back to a bud.

 Before removing any stem or branch you will need to assess the vigour of the tree and that of the branch you want to prune. I will list the 3 grades of vigor and what can be done on that branch depending on that vigour. Vigor will be less on trees that have been re-potted in the last year.

• No buds on the branch mean the branch is weak. Leave these alone (will probably die back)
• One bud on the branch means the branch is slightly weak. Don't trim or prune this branch, only pluck needles and wire if needed
• Two or more buds on the branch mean the branch is showing vigour. This branch can be needle plucked, wired, trimmed, and pruned. (Trimming is minor and pruning is major)

A vigorous branch. At the base of the branch, you can see a few 2-year-old needles. By my fingers, you can see last years needles. At the tip of this branch, you can see this year's needle growth and some buds which will flush out next spring.

Cutting back growth to a bud further back on the branch. (You can go further back as long as there is a bud there) Cutting back where there is no bud could cause die back if the branch is weak or back budding if the branch is vigorous.

Pruning: This involves cutting larger branches and requires you to have a concave or branch cutter (if you have neither, a sharp pair of secateurs will do) The best time to make strategic pruning cuts on a Spruce is in Autumn when the sap flow is slow. Don't remove more than one-third of the tree's foliage when pruning. The overall shape you are trying to achieve is a triangular silhouette where the top of the tree is highest. Unsightly branches should also be removed. This includes dead branches, branches that cross over each other, and branches that hide the bottom third of the trunk. Create space so light and air can enter the tree. Use your best judgment as these rules are only guidelines

 Wiring: Wire the Spruce from late summer to late autumn. Wiring and styling during this time reduce dieback of branches. The spruce branches are fairly flexible bend well into position. The average time it takes for the wire to set a spruce branch in place is 6 -10 months. Large branches may take longer and during this time you must remove the wire and reapply to avoid scaring. Ensure you are using the right thickness of wires for each branch. A general rule of thumb is that you should apply wire that is roughly 1/3 the thickness of the branch you are planning to wire. Remember to check on the wire that is applied in summer as branches thicken quickly during this time and the wire may cut into the wood and leave marks. When wiring, try to turn any straight growth into curves (this includes the trunk and branches. Old trees tend to have twisted trunks and branches, so we copy nature here. The spruces branches can be tricky to manipulate so bend with caution here.

Pests and diseases: Spruce can become host to scale and spider mites. If the foliage is not thinned and is too dense you will find yourself hosting cockroaches and spiders.

Bonsai Difficulty: ★★★☆☆