Even with the perfect soil, ideal location, and healthy flowers, if you don’t plant at the right time your garden will be ruined. Flowers don’t do well in weather that is too cold or very hot, so go with the time in between these periods: spring. Although planting in the spring may seem obvious, there is an art to choosing the perfect time. Wait to plant flowers till at least two weeks after the most recent frost, and avoid planting until temperatures at night stay above freezing on a regular basis.