To ensure the proper growth of ornamental onions, it is recommended to fertilize them with horn shavings, horn meal, or brown grain until the plant starts to flower. Once the plant begins to flower, the bulb ripens, and the fertilizer is no longer absorbed. At this point, the leaves may start to turn yellow and wilt. It is important not to cut off the foliage until it has completely wilted, as the plant stores nutrients in the bulb until then. Cutting off the foliage too early can steal energy needed for flowering the following year.
When planting ornamental onions, it is best to plant them in the background or alongside perennials such as lady’s mantle, geraniums, peonies, or catnip. This can help hide the yellowing leaves and fill the space once the onions have wilted. The ideal time to plant ornamental onions is in autumn, in a sunny or partially shaded location. Ensure proper drainage by filling the bottom of the planting hole with sand or gravel before planting the bulb. Leave the bulbs in the ground even after flowering, as they are very hardy.
By following these planting and care tips, you can enjoy the beauty of ornamental onions in your garden while ensuring their continued growth and success.