Landscaping & Design/japanese magnolia

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Question
My father planted a japanese magnolia in a garden bed approximently 6x16 but the tree will be surrounded by sidewalks rite outside of garden bed. I think as the tree matures I will have a.problem with root system. The tree is now maybe.5 ft tall by 3 ft wide. I think this will be the third summer for growth. Should I transplant the tree asap? What do you think is the best strategy for this tree/ flower.bed. p.s. tree is surrounded by hydrangeas..love to have your wisdom in this.
Thanks,
Sheri

Answer
There are several varieties of Magnolia, both deciduous & evergreen, and come in different sizes*.  While most stay small (15 ft tall x 10 ft wide) some "Japanese" varieties can get about 30 ft tall x 30 ft wide, when full-grown. All have a fleshy, shallow root system that can lift pavement later in life as they mature & get bigger. The farther away from the pavement, the more time it will take for it to occur - Not "if", but "when", in my opinion.

It comes down to what variety was planted.  If it is the smaller type, you should be OK for the next 20+ years.  If it is one of the larger varieties, then, yes, transplanting to a more suitable location is in order.  An alternative would be to install a root barrier at the edge of the pavement now, before the roots have a chance to reach that far. This is a heavy plastic dike that runs 18"-24" deep, perpendicular to the paving edge and directs the roots down & away from the concrete.  Just google "root barrier" for many examples of this product.

Southern Living magazine had an article with good advise on where to place these beautiful southern gems, as they are just as susceptible to root compaction & over-fertilizing, as they are causing problems lifting pavement. http://www.southernliving.com/home-garden/gardens/magnolia-trees-00400000065893/  

Hope this helps!  ~Marc

*3 Magnolia varieties, referred to as "Japanese" here (Chicago area):
http://www.mortonarb.org/tree-plant-advice/article/865/recommended-magnolias-for

*6 Magnolia varieties here: https://www.willisorchards.com/category/japanese-magnolia-trees

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Marc Chapelle, RLA

Expertise

I am a licensed Landscape Architect. I can answer general questions about style and design, give you ideas and suggestions for site amenities, help with larger site-planning issues, or perhaps give guidance for recreational amenities & park design. IF YOU ARE GOING TO ASK FOR A PLANT SUGGESTION GO HERE: http://www.growit.com/PlantInfo/LandScape.htm I prefer you ask somebody else why your petunias are not as perky as they should be; I'd LOVE to tell you how those petunias can increase your home's value!

Experience

20+ years of working with homeowners, contractors, developers and local civil engineering/architecture firms. I am located in the dry Great Basin area (Greater Nevada/Utah), so the use of landscape materials OTHER than plants is emphasized. As a licensed Landscape Architect I've worked on both the East and West Coasts.

Organizations
ASLA (ASLA.org)

Education/Credentials
BSLA in Landscape Architecture,Licensed in NV, CA, & VA - but can answer Q's across the country Many additional seminars, educational venues, and classes (both taught & attended)

Awards and Honors
Best Multifamily project, Reno/Sparks Builder's Association Best Model Home Landscaping, Reno/Sparks Builder's Association

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