My soil has very good drainage, sandy in texture. I have ordered three Yucca filamentosa "Color Guard" to put in a spot that gets all day sun. I haven't been successful getting anything to grow in this spot because of the hot afternoon sun. So...thought I'd try Yuccas. I also ordered one Yucca aloifolia "Variegata" to go in a rather large spot that is also a hot dry area. My question is, how much soil conditioners will I need to add. I have not grown Yuccas before, nor do I know anyone in my area who does. I hope I haven't made a big mistake in taking a chance on these Yuccas.