Joe and Alani My understanding is that Roundup (Glyphosate) works by interfering with/preventing the cell division of root tips. Thus, very effective on plants with limited energy reserves such as seedlings. Broadleaf plants seem able to deal with the stress of being sprayed better than grasses. Plants with reserves, such as many bulbs, and plants in a dormant stage without actively growing root tips, may be much less damaged. My limited experience is that bulbs and woody plants may show damage the next growing season with distorted and variegated foliage, and some growth setback, but will survive. Stage of growth, ie late in the season when the bulb is going dormant, would be the most favorable time to spray. There are sources that declare Roundup to be inactivated in the soil, etc. My suggestion would be to use caution, test and observe before using a weedkiller. If it is a situation where weedkiller is the only feasible solution, then you do what you must. Ken