Buddleja `Miss Ruby` is a new and distinct variety of butterfly bush that has the following unique combination of desirable features that are outstanding in a new variety. 1. Moderate vigor resulting in compact growth habit. 2. Ease of asexual propagation using softwood or semi-hardwood cuttings. 3. Upright growth habit with flowers borne stiffly on upright shoots. 4. Low female fertility and reduced seed set, resulting in less opportunity for seedlings to originate in the landscape setting. 5. Bright pink flower color, unknown in any other butterfly bush variety known to the inventor.