pinus strobus

Pinus strobus – Bonsai BCI

Pinus strobus

Frequent Title:

Jap White Pine

pinus strobus

Basic info:

Jap White Pine has tender blue-green Three to five inches lengthy needles borne in teams of 5 though foliage color varies enormously from one tree to the subsequent. It’s the solely five-needle pine native to the jap a part of North America and is the state tree of Maine and Missouri. Some specimens maintain the bluish color all through the winter, others free it. Though it may develop 100 to 120 toes tall with a 3 to five-foot-diameter trunk and unfold 50 to 60 toes, it’s sometimes seen from 50 to 80 toes tall in landscapes. Development may be very speedy at first however slows down with age. A number of branches on younger bushes usually originate from the identical level on the trunk forming a tree showing to be constructed of layers of foliage. Though younger bushes are pyramidal and normally develop with one central chief, the layers (or whorls) of horizontal branches give White Pine a particular look in center and previous age. The grey bark on the trunk and enormous branches stays unusually easy by way of center age, breaking apart into elongated blocks in previous age. The flowers, female and male, happen individually as small cones on the identical tree. The cones are slender and thornless, four to eight inches lengthy, and tapering.




Full solar.


Zone 3B by way of 7. Watering: No info accessible.


Simon and Schuster’s recommends feeding 5-needle pines as soon as a month from early to late spring and from finish of summer time to late autumn with a slow-acting natural fertilizer, and making use of chelated iron 2-Three instances per 12 months.

When you want to make use of chemical fertilizers, feed each different week throughout the identical instances with a half-strength answer of a fertilizer for acid-loving vegetation, comparable to Miracid. It’s possible you’ll want to alternate with a balanced fertilizer comparable to Peter’s 20-20-20 relying on the acidity of your soil combine.

Pruning and wiring:

The foundation system must be pruned step by step within the coarse of repotting, in order to all the time depart a robust root system. Department pruning and wiring must be completed in late autumn, and the wire left on the tree for 6-Eight months at most. Pinch new shoots in spring to 1/Three of their size.

Standard knowledge signifies that the needles of Pinus strobus don’t cut back properly, making it appropriate primarily for bigger bonsai.

Each 1-2 years it’s doable to take away the entire new shoots in late spring, if the tree is wholesome and well-fed. It will lead to buds forming within the fall on the websites the place the shoots had been eliminated. The explanation this may be completed is to kind very brief internodes on the branches.




Repot each 2 or Three years for younger bushes (as much as 10 years) or each Three to five years for older bushes. Repotting might be completed in spring earlier than the candles open or in late summer time or early autumn, after the warmth of summer time has handed. These are the 2 intervals of best root development in pines.

Due to the rugged high quality of the five-needle pine, a robust rectangular pot must be used. Pines want a deep root system, and five-needle pines particularly want a deep pot to keep away from uprooting by wind, as a consequence of their dense foliage. Simon and Schuster’s recommends 50% soil, 10% peat, and 40% coarse sand. Rémy Samson recommends 1 half leaf mildew, 1 half loam, and 1 half coarse sand. Peter Chan recommends Three elements coarse sand, 1 half peat, and 1 half loam.

Pines and different conifers develop in affiliation with a symbiotic fungus which grows within the root ball of the tree. If this fungus isn’t current, the tree could die. Because of this, pines and different conifers ought to by no means be bare-rooted, until steps are taken to re-introduce the fungus to the repotted plant, comparable to making a slurry (skinny mud) of the previous soil and pouring it over the newly potted soil.

Some consultants really feel that it’s extra vital to make sure that the tree all the time has a wholesome root system with ample feeder roots than to fret about symbiotic fungi. They really feel that bushes usually tend to die from having their root methods lowered an excessive amount of directly than from not having the fungus current. Actually it’s good recommendation in any case to make sure the tree has ample roots.

Pests and illnesses:


White Pine weevil might be the most important downside. The larvae of White Pine weevils feed on the sapwood of the leaders and that is devastating to the tree. The chief is killed and the numerous shoots changing it kind a bushy head. First signs are pearl white drops of resin on the leaders. The leaders die when the shoot is girdled as adults emerge in summer time.

Some adelgids will seem as white cottony growths on the bark. All sorts produce honeydew which can assist sooty mould. European Pine shoot moth causes younger shoots to fall over. Infested shoots could exude resin. The bugs might be discovered within the shoots throughout spring.

Bark beetles bore into trunks making small holes scattered up and down the trunk. Careworn bushes are extra inclined to assault. The holes seem like shotholes. Maintain bushes wholesome.

Sawfly larvae caterpillars are variously colored however typically feed in teams on the needles. Some sawfly larvae will flex or rear again in unison when disturbed. Sawflies may cause speedy defoliation of branches if left unchecked.

Pine needle miner larvae feed inside needles inflicting them to show yellow and dry up. Pine needle scale is a white, elongated scale discovered on the needles. Pine tortoise scale is brown and located on twigs. Relying on the dimensions, horticultural oil could management overwintering phases.

Pine spittle bug lives and hides in a foamy mass.

Spruce mites trigger harm to older needles, and are normally energetic within the spring and fall. Mites trigger older needles to change into yellowed or stippled. Zimmerman Pine moth larvae bore into the trunk. The one outward signs could also be loss of life of elements of the tree or plenty of hardened pitch on the branches.


Procerva root rot kills many White Pines planted off website. Keep away from planting in dry websites and clay or alkaline soil.

White Pine blister rust assaults White Pine and makes use of currant as an alternate host. European Black Currant, the favoured alternate host, could also be banned from sure areas. Different Currants, notably Purple Currant shouldn’t be grown inside 300 toes of Pines. Contaminated branches could also be pruned off. You should definitely choose White Pine bushes licensed to be rust-resistant.

Canker illnesses could not often trigger die again of panorama Pines. Maintain bushes wholesome and prune out the contaminated branches.

Needle forged is frequent on small bushes and plantation or forest bushes. Contaminated needles yellow and fall off.

White Pine decline is used to explain the gradual decline of bushes planted in dry, clay soils low in natural matter. Vegetation with this dysfunction have solely a small cluster of needles on the ends of the branches.


“Timber of the Jap United States and Canada” by William M. Harlow, McGraw Hill, 1942.

USDA Truth Sheet ST-473

Compiled by Sabrina Caine Edited by Thomas L. Zane 

Author: admin

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