How to prune a Large Magnolia grandifloria

[andy2]

i been asked to prune a large magnolia which is about 30ft in height.The magnolia is causing a lot of shade but they want to keep it "tree shape" so i said i can do a reduction and a slight thin.When is it best to do this i preserume to do it in winter as it will be dormant?Cheers

[Peter]

Magnolias flower on the previous season's growth, so immediately after flowering if they dont want to lose flowers, otherwise whenever is convenient.

[mdvaden]

Would imagine that your summer might be cooler than here. We don't have hot summers, but do see occassional 90 to 100 F. / 32 to 37 C. in July or August.

 

So I rarely remove top growth after March so the top can acclimate. We've seen near 100 F. in late May before. Which would amount to sunburn tissue on top if I did a late April to early May top growth removal.

 

 

I try to time for late October to like March or early February.

 

Your summers are cooler though, yes?

[treesnakey]

I recently pruned one about a month ago. i read to prune at the end of july, as pruning points they take a long time to heal.

 

I gave it a 20& crown reduction and thin. if thats any help.

[stihllearning]

be carefull when thinning, as grandiflora shade leaves tend to go black and die when exposed to uv. ive got two that i trimm every 2 years and i leave it till just after christmas when its grey and miserable.

[Tony Croft aka hamadryad]

Lovely tree the grandiflora, responds well to pruning too.

 

like the others have said, go gently, All magnolias rot easy so minimal size of cuts possible and I would do it mid winter. cuts will then get a full seasons closure and the foliage will adjust to the light differences.

[andy2]

Thanks lads,when i first read the comments when only peter posted,so told the customer ill do it next thurs.So ill do a light reduction, as they said they want me to come back each year and mangage there trees.

[Tony Croft aka hamadryad]

patience is a virtue dear boy! lol

[nepia]

The good ole Rupture & Hernia Society say prune grandiflora in spring as growth begins and lightly in mid-summer. A spring prune would avoid your light sensitive leaf issues I guess as the sun is weak then so newly exposed leaves can acclimatise.

[TArrryan]

a Magnolia I recently pruned by 20% after flowering reacted very unexpectedly, Instead of dropping its leaves one by one as it goes along it suddenly decided to drop all old growth and replace it with fresh!! didn't affect flower production though