"I'm thinking to plant a bracken's brown and then 4 feet over planting a nootka and repeating, so 4 foot spacing between trees. Is that too tight? "

A 4 foot spacing for the magnolias is far too tight!! These will develop a canopy spread of 15-30 feet in time so a 15' spacing is the bare minimum you should be considering. And forget the Nootka cypress entirely.........not a suitable companion planting and NO room anyway!!!

A really bad idea overall. Sorry :-(

I know the tighter you space things the less tall they might get === I DOUBT THIS COMMENT

and also might decrease lifespan slightly === SAME HERE

but hopefully it all works out. == FOR YOUR SAKE.. I HOPE IT ALL DOES.. BUT KEEP IN MIND.. WHEN WORKING IN BULK.. EXPECT SOME LOSSES ..

I don't want the nootkas to get more than about 40 feet === NO TREE EVER STOPS GROWING IN HEIGHT.. PERIOD ;..

so maybe the bracken's browns root competition won't allow nootkas to get too tall == AGAIN.. I DOUBT THIS ...

====

i wouldnt bother with any fert ever.. and would rely on the free wood ships naturally rotting and improving your soil ...

they will need to be watering in the year of planting.. and in the second year if drought .. and after that they should be rather free range.. i would NOT install permanent irrigation ...waste of money and water ... whatever you use.. plan on removing and reusing it elsewhere ..

ken

As has been mentioned, no less than 15'-20' apart for Bracken's Beauty magnolia. You could underplant with Little Richard or other abelia , which mixes well with Magnolia grandiflora.

Abelias are full sun plants and Magnolia grandiflora produces what has been described as "a tar pit of shade". Otherwise 20 ft. across is small for M. grandiflora and I've not noticed 'Bracken's Brown Beauty' being described as a dwarf selection.

Abelias do just fine in part shade. I have many planted in my yard that thrive under Magnolia grandifloras. They are also great for hiding the copious leaves that fall from the magnolias.

permanent drip irrigation connected to the existing sprinkler system I think is a good idea.

A) I read no, it's not just the first couple years need water that many trees still need additional water for like the first 5 years being a common mistake of why trees die,

b) this past summer's drought and heat waves were so bad that mature established arborvitae died all over the place, not just younger ones with smaller root systems but emerald greens 10 feet high that had been there over 10 years, green giants 16 feet high, and smaller globe types.

I didn't see any other species affected except rhododendron even in shade which they prefer but at least these are showing new growth and can be dead wooded whereas the arbys are all basically brown and crispy and saw some leyland cypress some either completely brown or with spots or some limbs brown, some mature established up to 17 feet tall.

Also doesn't hurt to fertilize the landscape besides the grass if it's done right.

I did read (no reference) somewhere the closer you plant they shorter they grow and possibly lifespan because the root system competition, makes sense to me.

ok, if "no tree just reaches a certain height and stops growing", but most will have spurts to a certain height and then be very slow growing maybe 6-12" a year which I'm ok with and not worried will become twice what I expected and be a damage-hazard if it falls.

WHY is nootka cypress not a good companion plant? What is that is similar? I think this person who nay-says on the first comment on almost everything I post now here is mad that I once argued back about wanting to plant only long-lived trees, so the landscape lasts generations, they said no, people change their landscapes all the time and want their own idea. But I think if it's not broke don't fix it.

If the trees have clear space to root on all 4 sides except where it joins the next plant, which isn't nearly as bad as say a driveway or patio etc where the roots won't get oxygen or water , how bad would it be to plant them say 6 feet apart? I want them to make a full screen starting at like 6 feet near the fence top.

As with many species there's conflicting max height and width specs online and on tags. The tags for these bracken's say about 35 feet tall and 22 feet wide, which come to think of it IS a stout tree with the base being wider than expected, but the lower 5-6 feet of the base will likely be skirted back eventually so it doesn't take up yard space and can be walked under but still block over the 6 foot fence. So if the widest area being the base would be about 20 feet, that's about 10 feet spacing but 6 feet up the trunk once skirted width would be more like 7 feet apart, so to plant 7 feet apart doesn't seem too close, these aren't the most dense trees so I don't think any mold etc will be caused if they're packed a bit closer than suggested. Also the nootkas might prefer some of the closer shielding in hot weather and vice versa for the bracken's in winter winds (although would only be on 2 of 4 side.

IDK I'll probably end up doing something like 7 foot spacing. I have several customers where emerald greens died this summer and can plant them the leftovers bracken's after hi-lift jacking the arby roots out.