Can I prune this magnolia?

I have become the volunteer gardener for a not-for-profit art studio housed in a brownstone in downtown Boston. It has a decideous magnolia tree in the front that I'd like to prune because it is too close to the building and also it shades the garden space underneath so that it is hard to get anything else to grow. The tree was here and already large when they purchased the building over 15 years ago. It blooms beautifully in the spring. It is the pride and joy of the studio garden so I can't do something that would risk killing it. I was thinking to cut the 4 small trunks at the soil level and leave the 3 big ones. See pictures. This will also raise the canopy up a little helping the light underneath. Then I'd head the branches in the back where they touch the building.

Is this safe without destroying the tree and what is the right time of year to do this?

Thanks,
PD Stimpson

 

Probably best to leave it alone as it is rather far along in development for major structural alterations. It's also rather sparse. And the pruned-out trunks will re-sprout.

An exception would be if when looking at in flower or leaf you notice that the skinny stems are rootstock sprouts, with different parts than the main part of the tree.

If it is all one plant and not instead grafted the smaller shoots can also be seen as a way for the specimen to renew and perpetuate itself. If the main stem with the partly decayed base breaks off later in a storm, and you have removed the younger basal sprouts (and kept re-growth pruned out) there may not be too much left at that point.

 

Hard to tell - but looks like best left alone.

Although, one small stem looks like it could be removed for now if it does head upward, but not much outward.

 

Thank you, both, for your helpful replies. On your advice, I will refrain from pruning.

Thanks,
PD

 

Bed looks like it needs to be mulched.

 

Hi Ron, how much mulch, with what, and why? Is this a winter mulch or year round?
Thanks,
PD

 

Have a look at this.

http://www.puyallup.wsu.edu/~Linda Chalker-Scott/Horticultural Myths_files/Myths/Wood chips 2007.pdf

 

Thanks. I've read the pdf. I think it will help the garden significantly to mulch as the soil is dry and powdery and slow to absorb water. I'll follow the advice and put a layer of compost down first then mulch.
Thanks for the advice.
PD