Lobelia Seeds - Cambridge Blue77 84 days. Cambridge Blue lobelia is brilliant, easy to grow from seed, and perfectly suited for many humid and temperate climates. Cambridge Blue seeds will excite your home, patio, and garden with fast growing 4 6 tall lobelia with tubular powder blue blooms. Cambridge Blue lobelia seeds are vigorous garden performers and ideal for kids or novice gardeners to try as vibrant accent to flower beds, fences, and walkways. 1000 multi seed pellets. These