Wicked Winter Pots: How to Make the Best Cool Season Container Display wallacegardencenter Mini Hanging Planter Three years ago, I cross pollinated two amaryllis (Hippeastrum). This year, all 48 plants I started from those seeds are blooming for the first time. : r gardening Plant your poppies when it's cold! Poppy seeds require a period of cold to germinate and grow, so they generally do best when planted in the late fall or early spring.