By Tonyat8
United Kingdom 
Steragram. Thanks for your prompt reply.
My garden is made up of 3 rows of 3ft x2ft slabs with 2 removed from the middle row making the plot 4ft x 3ft.
The garden faces east and due to surrounding buildings receives the sun from about 8.30 to 12.00.
I agree it's not big enough for 2 pyracantha to grow but I didn't plant them together, but had 2 attempts. I'm not sure exactly when I planted them but it was at the beginning of the season as I bought them at a garden centre as being ready to plant. I also bought 42 for my back garden which are all doing well. The 2 that I planted in the front garden at different times lasted about 6-8 weeks before dying off.The hydranger I bought in July was a well established flowering plant but began to die off within days of planting.
The soil is moist and deep and was actually a bag of compost mixed with the soil at the time of construction of the garden. The garden immediately next to mine is totally neglected, unless I dig out the occasional sycamore. The garden on the other side next to me has roses flourishing.
As my main garden is the back garden I need to have something that doesn't need much attention in the front garden.
I only use systemic weed killer on the perimeter of the front garden
29 Aug, 2013
That's baffling and very disappointing. Makes you wonder if there is something toxic found its way into the soil. I'd try putting in a cheap and tough perennial such as a perennial geranium and stick in a few daffodil bulbs and see what happens to them, I certainly wouldn't risk any more money on shrubs until its sorted.. If you want some colour over the winter why not have a euonymus fortunii in a pot. You can stand it on the soil and still get the effect of something growing there for now.
If I've understood you your garden is six feet wide? A mature hydrangea could fill this almost completely and I'd think twice about it if you want long term planting.
Sorry I'm not much help. If the hardy perennial dies as well I'd think seriously about getting the soil tested.
30 Aug, 2013