Forest Garden Design

Hi everyone

I started a thread on tree spacing, but although on the same topic, this is specifically about my design so I've started a new thread.

This is about my small allotment plot.  Being small it is more challenging to apply certain principles, but akin to what most people may have as a small back garden in the UK, plus it is less rigid in design to my other plot and can be planted more like a forest.  Approx 13.5m x 3.5m in size.  The longer dimension being in the East - West plane, and sloping slightly downwards at about a 3 deg drop, so about 70cm drop i.e. an east - west facing slope.   The location is South East london.  

The greenhouse, and curved wall of greengages, are installed, and won't be removed, as this creates a little social area I want to keep.  All the plants listed have also been purchased so I would like them to go in (they're all currently about 2-3yrs old).  In between all the spaces will be footpaths, and other shrubs and ground cover, as yet to be planted but will be put in according to space and shade requirements.

So the main trees to the west of the greengage wall design is flexible (there is also a small amount of space free to the south of the greenhouse).  I've put together a few scenarios which I'm attaching to the post including a sketchup model

I've colour coded them based on sun/shade requirements from Martin Crawfords book.

Yellow (Prefers full sun.  Tolerates no shade.)
Orange (Prefers full sun.  Tolerates light shade (min 4.5hrs direct sun per day))
Green (Prefers full sun. tolerates moderate shade (min 1-2hrs direct sun per day)
Blue (Prefers full sun.  Tolerates fairly deep shade.  (No direct sun but some indirect light))

None of the plants are that tall, which does create some issues.  I have shrubs which will potentially grow to 2.5-3m tall, whilst some dwarf trees will supposedly get to 1 - 1.5m tall which doesn't fit the neat layering or understorey pattern of canopy trees, fruit trees, shrubs, herbs, ground cover etc.  There is a height restriction here, so the shrubs are at the top end.  


Not sure if it's clear from the images but the plants are (expected height x spread):

Yellow: Siberian pea tree (1.5m x 1m or 5ft x 3.3ft), Dwarf Almond (1m x 1m or 3.3ft x 3.3ft), Dwarf Mulberry (1.5m x 1.5m or 5ft x 5ft)
Orange: Carolina Allspice (2.5 x 2.5m or 8.2ft x 8.2ft), Strawberry tree (arbutus) (1.8m x 1.8m or 6ft x 6ft)
Green: Mountain Pepper  shrub (2.5 x 2.5m or 8.2ft x 8.2ft)
Blue: New Zealand Flax (1.2m x 1m or 4ft x 3.3ft), red Currant bush (1.5 x 1m or 5ft x 3.3ft)

Unfortunately I've been over this so many times, I've over-thought it and confused myself.  Basically I want to follow forest garden principles such as efficient spacing,  consideration of shade/sun requirements, diversity, perennial planting, and nitrogen fixing etc

Any comments gladly appreciated.  

That big white rectangular wall to the south of the greenhouse is on the neighbours plot, and the only thing overshadowing my plot, but obviously can't be moved.  It's just some blackberries on a trellis.

Nice layout maps!  So the shadows shown in the pictures is late in the day since South is towards your neighbor's blackberry trellis?  Is there a fence or vertical element along the North property line?  Maybe some trellising could happen there as well.  I'm not familiar with the term greengage, what is that?  Would you want to build a lattice or pergola over that and run some vines over the social area?

Mid-day sun is the most important for determining shadiness or sunniness, how far do the shrubs cast their shadows during the 10am-3pm timeslot in summer?  I think I like the 3a plan since it keeps the tallest plants to the north and the sun lovingist ones have good morning or evening exposure in addition to the south exposure.

Hi Mike.  Thanks for the reply.  Yes, the shadows are late in the day.  Just thought the afternoon sun is quite important, so I thought I would practice with that.  I understand that this is virtual, but I can tell you from experience that sketchup is not a million miles off.  Definitely worth trying

There is no fence or trellis along north line.  Oh the irony!!  My whole design a couple of months ago had trellises running along the north side (I presume you mean in the East-west axis), but I removed them, since I read that trellis in open space (say for an espaliered or fan trained fruit tree) should run north south, so both sides of the fruit get some sun.  Hoping this what kind of happens with the greengage (a plum)

Anyway, number 3 huh.  Great, will wait to see if any more votes.  As I said, am willing to move things around, doesn't have to be one of my designs.  Quite difficult.  The width of the plot if very narrow, and in reality, my trees and shrubs, albeit mostly dwarf, are probably a bit too large for the plot so it's really tricky to create that layered effect i.e. short at the front, tall at the rear.

My main concern has been the shadows cast from the western side to the eastern i.e. if trees or shrubs are in a line running east to west, that the western most plant casts afternoon shade on the next plant and so on.  Leading me to think of ways to somehow stagger the plants.  It does get rather complicated then, and from my other post I wrote on that subject, I don't see many designs that even take this into consideration.  I guess I should probably just be allowing say at least a foot of space between trees and shrubs, so some sunlight can get to their east and west faces.  Hope that makes sense

Looking forward to more comments

Thanks again

Have you read these books?

https://www.amazon.co.uk/Edible-Forest-Gardens-2-Set/dp/1890132608

My first instinct looking at your design is that it is going to be too densely planted. A lot of the benefits of forest gardening accrues from edge effects - where high trees meet lower trees, meet shrubs meet ground plants - and a lot of the most productive designs are a broad mix of open space and trees. I don't know your location/climate, but where we are such a dense planting would really restrict productivity of the understory layer.

My opinion is that if you have the trees/shrubs generally unshaded from 10-3 you'll be in good shape.  Any extra you can get before or after that is great but not nearly as critical.  Keep in mind, that sun is pretty high overhead in summer so the shadows are quite short in the middle of the day.

I think trellises for agricultural production may do better when run N/S but I wouldn't blink at trying it E/W.  Most of the growth and fruit will be on the South face so just put the trellis on the North property line and you'd be all set.  In your particular case the trees may shade a trellis too much when they're full sized but maybe you could get a yield for a few years before that happens.