Dig a small hole near the heather's roots. Healthy roots are white. If the heather's roots are white the plant is still alive. If the heather's roots are brown, red or black the heather is dead or dying.
Will my heather come back?
Heathers do not regenerate well from old wood, so once they have become woody and leggy, replacement is the best option. Alternatively, consider propagating the plant by 'dropping' (see propagation section).
How do you keep heathers alive?
Water fortnightly for the first 3 months to keep the ground moist but not sodden. Drought tolerance is normally established within 2-3 years from planting, after which time your heather plants will take care of themselves. Until this time, water as required to keep the soil evenly moist, but never soggy.