Correct landscaping and planting can help to maximize the performance of a Passive Solar Design and can help solve all sorts of problems with imperfect sites and situations.
Deciduous trees and vines in the right place can help to shade the building in the summer while letting in sun in the winter.
Evergreen trees to the south and south-west can help to shelter the building from cold winter winds.
In the case of the Greeny Flat the site was already pretty perfect so the main concern in the landscaping plan was not to mess things up. We have raised beds around a patio on the north side for growing herbs and vegetables for the kitchen and we have planted two small, deciduous, apple trees on the north side. These will be kept pruned to a low height to ensure they do not block any sun from the building in winter. On the south side we have created a graveled courtyard between the house and the retaining walls with a small area of low-water use planting. In general the landscaping is minimal.
Landscaping can be used to improve an imperfect site. When the above passive solar home was built in Glenquarry twenty seven years ago the site had one major flaw… it was very exposed to the south west, to hot winds in the summer and to very cold winds in the winter time. Over the years the owners have planted a thick forest of fire-resistant shrubs at the west end of the building (the far end in this photo). This now provides a wonderful wind break which makes the whole house much more energy efficient and makes the patio on the north side a much more enjoyable place to sit (even when the wind’s blowing).
Thoughtless landscaping can render a Passive Solar design almost useless. This photo reminds me of a house I inspected in Montana that was designed and built as a very effective passive solar home way back in the seventies. Unfortunately the original owners sold and the next owners decided it would be a cute idea to plant their little Christmas trees out in front of the house for a few years running. By the time I saw the house (in 2011) the trees were about 150 feet tall and the poor house got no sun at all. This rendered the passive solar design completely useless.