I cut down eight conifers, hollowed out the stumps to a depth of about five inches and drilled a drain hole. What type of soil should I fill them with and what mixture of shrubs and plants would be best suited?
That’s a creative solution to what I imagine was an ugly hedge. The depth is not nearly deep enough for a shrub; you’d have to water endlessly and even then they may sulk. You will have more luck with tough perennial plants.
The wall bellflower (Campanula portenschlagiana) is evergreen, flowers all summer and requires a small root run. I think heucheras will also do well; Heuchera villosa ‘Palace Purple’ is hard to kill and can tolerate fairly deep shade. It has dark purple leaves and tiny white flowers in summer. Hardy succulents such as sedums are a good choice. They have bright yellow flowers and won’t mind tight root conditions. Look for cultivars of Sedum rupestre, S. cauticola and S. spathulifolium, which will cascade over your conifer pots.
Buy good quality peat-free multipurpose compost and mix three parts with one part grit to ensure good drainage. Give the odd liquid feed through the growing season or add a handful of chicken pellets.
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