Saskatoon Obelisk A cultivar of the Alder-leaved Amelanchier or Saskatoon, Amelanchier alnifolia Obelisk is a very upright shrub or small tree with good autumn colour, colouring best in acid soil. Pretty, fragrant white blossom in spring is followed by round, red, edible berries which mature to black in June. These cook to a sharp, rich red and are good in jams and smoothies – if the birds don’t get them first! A large, conical shrub, it can be pruned to a central stem to make a small, slender tree. Site: Semi-shelteredSoil: Any fertile well-drained soil; lighter, acid soils preferredPosition: Full sun or partial shadeSeason of Interest: Spring, summer, autumnHardiness: Fully hardyHeight: 13-26ft (4-8m) in 10 years Spread: 3–5ft (1-1.5m)