I was wondering what I could plant under a 10-20 year old Colorado blue spruce, the soil is heavy clay and because it is a spruce the soil is acidic. we have tried hostas but as they do not like Acidic soil we have had them slowly decline in health even die. Is there any other plants that could brighten up the area and flourish, either ground covers or flowering plants?
mostly looking for perennials (I live in Mississauga Ontario so i believe it to be zone 5a)
To be truthful it is very difficult to get plants to grow under a large, well established spruce trees. The soil under the tree will lack nutrients, will be very dry, shady and as you stated is acidic. Planting in and around the roots of a very mature spruce can be a challenge. What type of plants will fit the criteria of acid conditions, be shallow rooted and tolerant of the spruce’s roots? There’s not many. Your best bet for adding colour to the area would be to use containers to fill in under the spruce. Container grown plants can be placed as desired and you can grow whatever type of plant you like. The plants will not have to compete with the spruce’s root system because they have their own pot. Adding splashes of colour from flowering annuals can make a real impact when they are grown in a container under a spruce.
Some people have had success planting periwinkle (Vinca minor) as a ground cover under spruces but that wouldn’t create a “wow factor”.