Question
QUESTION: how far should i be planting away from the foundation? i am thinking of
planting the following as foundation shrubs but want to avoid problems with
deep roots affecting the foundation.

-thuya occidentalis (globe cedar)
-viburnun opulus roseum
-dappled williw  (salix integra hakura nishiki)
-small leaved lilac (syringa micrphylla
-potentilla (pink)
-peonies
-juniper procumbens nana


i am in zone 5 and the front yard faces east.

thank you!

ANSWER: Ellie-

If you are worried about foundation damage, all the plants you listed are VERY tame.  I抎 plant them to within 2 feet of the foundation without hesitation.  The concrete is going to act as a root barrier to these plants, rather than being damaged by them.

-Thuja occidentalis - Globe cedar -'Bobozam' variety? There are many different types (globe & erect).  All are easy to grow & very adaptable, with little to no root problems, once established.

-Viburnum opulus 憆oseum??European cranberry bush is a very low-maintenance plant, but will get large in the right location (12 ft. tall x 14 ft. wide), so give it some room, and don抰 plant it under a window sill if you like the view.  Maybe pull it forward from the house by about 3 to 4 feet.

-Dappled willow  (Salix integra 慼akura nishiki? is probably the plant on your list that is going to give you the most root problems, but it is a small shrub, compared to its MUCH larger and invasive Salix/Willow cousins.  Just don抰 plant it on top of any sewer or water lines.  A beautiful addition to your garden.

-Small-leaved Lilac (Syringa micrphylla) will get up to 6 ft. wide, and 9 ft. tall.  This round, deciduous shrub also has well-behaved roots.  Its cousin, the S. vulgaris has naturalized in several states and is know for aggressive root-sprouting, but it isn抰 going to lift or damage a foundation.

-Potentilla (pink) There are over 100 cultivars, and none that have been reported as being problematic with their root system.  They tend to mound up, and out of the ground, as they get older.

-Peonies- no problemo.

-Juniperus procumbens 憂ana??more susceptible to root-rot than heaving concrete out of place.  A very low maintenance plant.

Hoep it helps alleviate some concerns.  ~Marc

---------- FOLLOW-UP ----------

QUESTION: Thanks Marc. Your reply has been extremely helpful. As a result, I will not be moving forward with the Dappled Willow since I am unsure about the location of the sewer lines.

However, the Viburnum opulus 憆oseum?is another matter since I really like this plant but fear it will be overgrown for the space when it matures. Would it make sense to prune this shrub to 6-8 feet high with a 4-6 feet spread or will it look totally ridiculous? If the latter, would you be able to recommend an alternative? I would really like to consider something similar to the white flowers and dark green foliage of the Viburnum opulus 憆oseum?but would like to keep the size to 6-8 feet high and 4-6 feet spread as mentioned. As it will be going under a window, I would also like it to be fragrant. Since the location is near the foundation, the soil is mostly normal to dry but with good drainage.

Finally, I forgot to ask about the root structure of the Salix purpurea 'Nana' - Dwarf Arctic Willow. I have planted this also around the foundation. I wonder if it will get any bigger than 3-4 feet high and wide.

Thanks so much for your expertise!

ANSWER: I'd just prune the Viburnum as needed to keep it in check...Shouldn't look too bad, unless you totally "poodle-ball" the thing with a hedge trimmer!  

We use the Salix/Dwarf Arctic Willow all the time here, and it is a real performer, but stays compact.  Not to worry about the foundation.

~M

---------- FOLLOW-UP ----------

QUESTION: Ok this is very good to know!

Hy husband has suggested I consider planting sambucus black beauty or black lace instead of the dappled willow and viburnum for their dark foliage. What you do advise regarding the root structure of these plants? How far from the foundation should these be planted? Is one variety better for zone 5 or are both equally good?

Thanks again! I promise this will be my final question. :)

Answer
Sambacus spp. has a thick tap-root.  Neither of these plants will be a root problem for your garden and foundation.  Biopth are hardy to your climate.  Maybe the Black Lace is a bit more cold tolerant than most Viburnum...

The Viburnum spp. is a large catagory.  Some are large shrubs, others small trees.  They come in cultivars that are Asian, semi-deciduous, or evergreen. (more info below)

Just keep them trimmed down to a managable size - the Sambacus have the potential to get 8 ft. tall if untrimmed, and the Viburnum (depending on which you pick) come in all manner of sizes, but can also be trimmed back.

More info on these plants:
Sambacus:
http://gardening.about.com/od/floweringshrubs/a/Sambucus.htm
Viburnum:
http://gardening.about.com/od/treesshrubs/a/Viburnums.htm

~Marc