Trees and shrubs can be started from seeds, as dry roots or potted seedlings. Generally the seeds need stratification (a cold or wet period) before they start germinating. Young plantings can be subject to deer and rabbit browsing, and likely will need some protection in the few first years. Some species require male and a female plants to come to fruition. There are so many species in this category, so make sure you do some research before you purchase and plant your species.