Where should I plant these Herbaceous Perrenials?

I have a raised bed space just outside a window (hence viewed daily and often) approx. 2 meters by 1 m with soil about 10cm deep.
I have just bought several plants which I am hoping will add a bit of colour to this viewed from the house area.

So far I have just planted a "rock plant" in each corner (sempervivum of varying types) the rest is just a mix of the soil and compost.

My question is. Out of the plants I have, should I just plant them all in or just a few?
Bearing in mind I have no idea how much these will grow and compete with each other or even if suitable for the area.
The area I want to plant them in is West facing so in theory it would be classified as full sun, I think.

Plants are Penstemon, Dianthus, Leucanthemum, Campanula, Lavandula.





As ever. Thanks for any help and advice . . . .

 

Hello Weedstoo The sempervivums don't need much in the way of food and water, but 10cm is pretty shallow, so the more of your other plants that go in, the more you'll need to feed and water them regularly. Unless the Lavender is a dwarf variety, eventually it will swamp the others.

 

Hi,

What is below the 10cm of the raised bed, general soil or concrete / flag stones ?

Can see the Lavender is Munsted which can get big but it will take a good few years to do that.
The Campanula - some are ground cover, some quite tall, cannot make out the name of it ?

The Dianthus, a smaller plant probably good nearer the Semps ..?

 

Hi. Campanula is - Carpatica Rapido Blue.

(Penstemon - Laura) (Dianthus - Purple Wedding)

(Leucanthemum - x superbum Madonna)

Under the raised bed is pure concrete slab so no chance of going deeper, only adding soil above to create a mound I guess . . . .

 

I think it would possibly work as a bed for alpine plants but 100mm depth is a bit shallow for most herbaceous perennials.

 

Not sure if the 5cm will make much of a difference, but I just went and checked with a tape measure, current depth is actually 12cm and will get that up to 15cm when I fill the rest with soil (so it will be level with the flat stones that border the whole rectangle).

 

I tend to think you will have a bit of a battle on your hands keeping up with watering and you will definitely need to keep feeding, once established.

You might be better going for annuals, half hardy.
Plant up in autumn for a spring show and then again in early summer with the annuals.

More work maybe, but I think most perennials will struggle after a short time being unable to get their roots down.

 

I have Penstemon "Laura" and it grows to be
Height: 90cm (36"). Spread: 45cm (18").

 

Hi,

Think we would put them into decent sized pots and stand the pots on top of the bed, as apart from the little Campanula and Dianthus doubt the others would manage to grow.

A possible way would be to cover the bed with some attractive gravel or shingle, but keeping things like the Semps around the edges and place the planted pots on the gravel, moving them around inot full view as each comes into flower.
This would allow you to keep a few more plants of varying size in pots elsewhere and bring them in when at their best.

 

Whereabouts is it located (and thriving)? As it seems I may need to find a different area to plant some of these due to soil depth.

 

I have been informed that there were possibly crocuses in there previously.

How do you think snowdrops would fare, as I might start thinking about adding some winter flowers to add to the "rock plants". Or does anyone else have any idea on flowers that would grow in 10-15cm soil depth along with the "rock plants" . . .

 

I have some in semi-shade and some in full sun.

 

Just my suggestion from earlier, but I'd be adding some grit to the compost and turn it into an alpine bed, might need to do some research into which alpines you like but I think it would be possible to just weed it and water if necessary, and the planting would be long term.

Like all things gardening, its about how much free time you have and how much maintenance you are wanting to do.

 

Perennial herbs would do well in a shallow planter. Thyme, chives, marjoram and rosemary for base planting and annual herbs and edible flowers for summer? Having a herb planter just by the house is great, a small sprig of fresh thyme makes any meal look posh

Small spring bulbs would fit in too, and a couple of winter seasonal pots could go in when the annual herbs come out. The Lavender would be ok with the herbs at least when young.

10cm is very shallow so the perennials you have will do much better in ground or in large (50cm) containers. The plants look very healthy and bushy, you are off to a good start already.

 

Hi. Struggling to find a place for the lavandula now (everything else has been planted).
The only suitable places viewing wise will be in shallow soil (full sun). Thoughts? Will it die in there?

I have tried to research this and I got conflicting information from "you nee 60cm of soil depth" (what??) to "I just put it in shallow places where it was not expected to thrive and it grew pretty much anywhere".