- ≡ Veronica subsimilis Colenso, Trans. & Proc. New Zealand Inst. 31: 278 (1899)
- ≡ Hebe subsimilis (Colenso) Ashwin in Allan, Fl. New Zealand 1, 929 (1961)
- ≡ Leonohebe subsimilis (Colenso) Heads, Bot. Soc. Otago Newsl. 5: 9 (1987)
- ≡ Hebe hectorii subsp. subsimilis (Colenso) Wagstaff & Wardle, New Zealand J. Bot. 37: 33 (1999)
- ≡ Hebe tetragona subsp. subsimilis (Colenso) Bayly & Kellow, Illustr. Guide New Zealand Hebes 321 (2006)
- = Veronica astonii Petrie, Trans. New Zealand Inst. 40: 288 (1908)
- ≡ Hebe astonii (Petrie) Cockayne & Allan, Trans. New Zealand Inst. 57: 39 (1926)
- ≡ Hebe subsimilis var. astonii (Petrie) M.B.Ashwin in Allan, Fl. New Zealand 1, 930 (1961)
- ≡ Leonohebe subsimilis var. astonii (Petrie) Heads, Bot. Soc. Otago Newsl. 5: 9 (1987)
Branchlets weakly to strongly tetragonous in cross-section; maximum width of ultimate branches 1.8–3.0 mm; internodes 0.5–1.5 mm long; lamina usually 1.4–2.5 mm long; apex sub-acute or acute, not keeled or keeled; edge of leaf at apex forming a 90° angle with adaxial surface and rounded to meet the abaxial surface.
V. tetragona subsp. subsimilis plants are generally smaller and less robust than plants of subsp. tetragona . Their leaves are smaller (although there is some overlap), less strongly keeled, and more rounded at the apex and shaped like the bow of a boat in side view.
Sub-alpine shrubland and penalpine grassland. Recorded elevations range from 762 to 1707 m.
Hybrids between V. tetragona subsp. subsimilis and V. odora are sometimes found. These plants have small, elliptic, sub-erect leaves 3–6 mm long.
Flowers: December–February(–April); fruits: (January–)February–May(–November).
2n = 40 (see Bayly & Kellow 2006, as Hebe tetragona subsp. subsimilis).