Recommend plants to replace or add to Firethorn on narrow plot in Philadelphia
We live in the Art Museum neighborhood in Philadelphia. We have a 15 x 1.5 feet plot outside our fence that has had Firethorn growing there for the last 20 years, but three of the Firethorns have died, and there are blank spaces. The Firethorns have suffered aphid infestations which we battle each year. Are there plants that grow about 5 to 8 feet tall that tolerate part sun (only at the top) and don't spread out more than 2 feet onto the sidewalk that we can use to fill in the blank spaces where the Firethorn died? Or should we just plant more Firethorn, even though they don't get enough sun any more?
Answer
You must be pruning the Firethorn to keep it in bounds. You could plant more if you want, but I am worried about planting more if some are dying. Firethorn is susceptible to fungus diseases. If you do replant with Firethorn, select a disease resistant one such as Pyracantha ‘Saphyr Jaune’. However I do have two planting suggestions: Ilex crenata ’Sky Pencil’ (evergreen, thornless Japanese Holly), which if unpruned will get to 8'-10’ x 3’ wide (it can be pruned to keep it at the height and width that you want and it responds well to pruning) and Buxus sempervirens 'Graham Blandy' (an evergreen Boxwood) which if unpruned will get to 8’X 2’. The Boxwood also responds well to pruning to keep it to the size you want. If you Google the botanic names of the plants you can see pictures and descriptions of the two suggestions. Also, online you can find places that you can mail-order the plants, if you cannot find them locally.
I hope the suggestions are helpful!