Hello all, New to gardening and my first post! I have recently redesigned my very small (and shady) back yard in Vancouver. On one side of the yard along the fence are 3 trees - a Japanese Maple, a Lilac and a Rhododendren. The entire yard (including under the trees) was covered in about 5 inches of pea gravel. I removed the gravel and replaced with a decorative pattern of concrete pavers leaving about 4 feet away from trees unpaved (not quite to drip line). I would now like to replace the pea gravel under the trees with soil and grow some shade plants between/around trees. Questions: Is there any problem for the trees if I replace the 5 inches of gravel with 5 inches of soil? Will the trees suffocate? What type of soil mix would be best? Previously there was a nylon garden fabric under the gravel (I suppose to prevent roots and weeds coming up through gravel). Can I leave this there and plant on top of fabric to prevent tree roots coming up through soil and causing garden to become root bound? Will I need to irrigate trees if I put soil/plants in? (Previously rain was sufficient although I watered some in July/August.) I'm assuming i'll have to water new plants anyway so am considering drip irregation system. Any suggestions on plants also appreciated. I was thinking of Lily of the valley, Trillium, Solomons Seal, ferns etc Thanks in advance for any advice or enlightenment. Rob
Rob, I've planted Dodecatheon meadia ( Shooting Stars )under my 70 ft oak tree along with yellow Trillums,Acidanthera and Sprekelia.I put in about forty -five tulips last fall and they were a glorious riot of colour for the last 5 weeks or so. I'd like to plant some ferns and camas but have not found them in the garden shops and I don't intend to help my self to them in the wild. My lily of the valley grow happily under a star magnolia that has been failing for some years now. When we first moved to our house 25 years ago there was a long unattended rock garden built up around the tree which we tore down .I use a bulb planter to plant around the bottom of the oak, don't try to keep the grasses, weeds,and volunteers out. I only water if it needs it and I put ground seed meal in the hole for every planting . They seem to have thrived so far.
There are many plants that thrive in shades. Peace lily or spatiphyllum is one of them. You can also use bromeliads which are less maitenance plants and will survive in that gravel so there is no need to replace it with soil.
Filling over tree roots can be quite detrimental, be careful about this. Otherwise, you might be interested in THE COMPLETE SHADE GARDENER by George Schenk. He gardened for years in Bothell, WA so much of the information is regionally based.
You might also consider leaving the gravel and planting in it. There are some shade-tolerant ornamental grasses, for example. Or, you could place pots of plants on top of the gravel...then you could grow lots of different shade tolerant plants. As Ron says, replacing the gravel with soil is fraught with peril. If you really want to do that, you might consider having a tree expert advise you.
