Sea Buckthorn shrub planting in the urban environment

What is an appropriate minimum raised bed depth/size for Sea Buckthorn to thrive, assuming an impervious surface?

This planting is part of an ongoing temperate climate urban garden project I'm calling the "Six Sisters Garden".  

I am planning on installing two -- one male 'Pollmix' and one female 'Leikora' variety -- Sea Buckthorn shrubs in raised beds.  The male plant will be planted upwind of the female plant for pollination.  The growing area will be in the sunniest part of the old playground, avoiding overstory tree cover.  

Shrub's original size is likely going to be from a 3L pot, 60cm height.  

Shrub's expected mature size:
Width 2 to 3 m
Height 3 to 4 m

Shrub's expected growth rate is 0.25 to 0.80 m / year.

The current raised bed dimensions I am planning on using for these Sea Buckthorns are 120cm x 80cm by 60cm deep, each.  

Most importantly, the design site will be a converted playground which currently has rubberized tile as flooring.  If the growing depth and volume of that bed sounds insufficient, I could either go up to 80cm depth raised beds off the bat (which I feel would look unbalanced compared to the shrub's original smallish height), or (more likely) I would remove rubberized tile flooring to allow the shrub plenty of root space to grow down underneath the tiling to the dirt below.

1) Does 60cm sound like a good raised bed size for a shrub, with or without the tile removed, provided that lateral growth size of 120cm x 80cm?  
2) If not, assuming these raised beds are stackable, could an extra 20cm of bed be added above the shrub's root flare at a later date with no detriment to tree health?  

My hope is to save those 20cm stackable layers and use them for annuals the first few years, and then, if the shrubs get unwieldly in size years down the line, then the clients could simply stack up to get sufficient root space for the Sea Buckthorns.

*Edit to add, if it helps...

According to this site over here.

The roots are located near the soil surface. The majority of the roots are located at a depth of 30 cm. The root system is much wider than the crown of the plant, reaching sometimes up to 4 m. Root system is fibrous, slightly branched.

It's photos time!

Here are some pictures of the raised bed preparations, along with some other fruiting perennials in the garden: Thornless Blackberries, Gooseberries, and Hardy Kiwi vines.  The hardy kiwi vines, of course, require expansive and sturdy trellising, and they are more shade tolerant; so they are nestled up against a strong fence under the partial shade of some trees, rather than in the sunniest part of the raised bed garden.  As a bonus, as they grow and climb up the fence, they will provide a bit of privacy and a cozy sense of place in the main seating area of the garden.

I have two sea buckthorns near my house. The female is older and grows crazy fast, but doesn't produce much. The male is tiny and looks fragile, but thrives.

Things to consider: my friend once said that fruits taste like vomit, and he was right. I never thought about that, because I only had a few and I mixed them in jams with plenty of other fruits. But once I tried a raw fruit puree made of 100% sea buckthorn and it does taste like vomit.
Spikes are long, strong, and there's plenty of them. Make collecting fruits quite a challenge. Great for deterring unwanted visitors, and for protecting small birds and other wildlife from cats, but your pets and kids can get hurt if they don't learn to be careful.

Otherwise, I would go for it. It's a lovely tree or bush and leaves make a great tea (this one tastes really good, thankfully).

Flora Eerschay wrote:I have two sea buckthorns near my house. The female is older and grows crazy fast, but doesn't produce much. The male is tiny and looks fragile, but thrives.

Things to consider: my friend once said that fruits taste like vomit, and he was right. I never thought about that, because I only had a few and I mixed them in jams with plenty of other fruits. But once I tried a raw fruit puree made of 100% sea buckthorn and it does taste like vomit.
Spikes are long, strong, and there's plenty of them. Make collecting fruits quite a challenge. Great for deterring unwanted visitors, and for protecting small birds and other wildlife from cats, but your pets and kids can get hurt if they don't learn to be careful.

Otherwise, I would go for it. It's a lovely tree or bush and leaves make a great tea (this one tastes really good, thankfully).

I don't remember which varieties I have, but mine are delicious.  I look forward to them every year.  My chickens also go crazy for them.

The spikes are fairly terrible.

Our Sea Buckthorn planting ceremony went wonderfully!  

A community leader and his wife together planted male and female Sea Buckthorns to dedicate this new garden.  And I had the privilege of guiding them and the audience in teaching how to properly plant a tree or shrub.  As the husband and wife untangled one of the root bound plants, we were all happy to discover a little worm hiding in there, now free to explore his giant new raised bed home!

Before the planting, the community leader gave a lovely speech, highlighting the significance of these plants as well as urban green spaces in general.  

Green spaces buffer the heat in local urban micro-climates, and can sequester carbon globally.

Edible green spaces provide not only fresh food, but places to connect with members of the community and nature.

The Sea Buckthorn has bright orange fruit, high in vitamin C; great for one's health.

The plants are Nitrogen-fixers, and thus can reduce our dependence on fossil fuel-derived fertilizers.

These specific plants need a male and female to produce fruit, paying tribute to how we can accomplish more when we work together.

P.s. Speaking of achieving more when we work together, thanks to an opportunity to lead two teams from a youth job-connection/volunteer organization, the Six Sisters Garden now has 6 new large urban raised beds, made from surplus pallets.  So now each of the resident families at this garden will have their own unique bed, in addition to the community growing spaces.  There are also two new raised beds for kids to use, made from pallet scraps.  And as I was building the little beds yesterday, one of the children from the center came by and helped me install the raised-bed liners.  She would pass me hardware bits, and even used the screwdriver all by herself to fix the liner to the beds.  In these two small beds she and I planted more thornless blackberries.  These 8 new beds are in addition to the 10 lovely foldable stackable ones pictured below during our ceremonial planting.

George, you are doing such a wonderful thing there! Building community as well as gardens. Hard work, but a blessing to your town and the planet!

Be aware they do sucker. And the suckers will bust up through black top / tar seal.

Personally I would use it as a hedge if you can deal with the suckers. However definitely get the cultivated varieties, the taste profile of the perfectly ripe cultivated version is a bit like orange juice compared to the battery acid flavour of the uncultivated.

I have 'Mary' and 'Sunny' for female and a 'Lord' as a male. Both fruiting varieties are very good one is more productive than the other and I think its Sunny as its a slightly lighter colour when its ripe. To help maximise the fruit production ideally you want a male for every seven females.