It may not be the plants fault, but the soil they are in. Different plants thrive in different soil types ranging from dry-porous conditions to wet and heavy soil conditions. Before purchasing a plant, be aware of it's soil requirements and try to duplicate those conditions as close as possible at your own home. This may mean the incorporation of compost, sand, or fertilizer to improve the health of your existing soil. If you are unsure, then consult a plant professional. Remember, the success or failure of your plants starts with the ground they are planted in.