Astromeria are awesome summer blooming bulbs and if you cannot find what you want at your local nursery or garden center you can order the bulbs online and have them shipped to your home. There are many  bulb growers that specialize in mail order such as Brecks bulbs and you can even use Amazon to order bulbs from growers.  You may have better luck getting the specific variety you want from an online order than from sorting through lose bulbs at a nursery. This is because the different varieties can be accidently mixed into each other when bulbs are sold from open bins to the public. Sometimes the mix ups come as a lovely surprise - like the year I planted dozens of soft pink tulips only to find one bright red tulip flowering in the middle of the pink. Gardening is an adventure. Keep growing, Marianne Binetti