Pampas grass (Cortaderia selloana) covered with rime appears in Ludwigsburg, Germany on March 12, 2010. Experts say some plants are more flammable than others but all plants can ignite under the right conditions. Those conditions include improper pruning, insufficient watering, and poor sanitation practices that allow dry, dead plant parts to remain on the soil surface. (AP Photo/Thomas Kienzle, File)