All flower types are subject to seasonality (meaning specific times of year when they're produced at high volumes and we're able to source them for you. Here's a rough sketch of when some of your favorite stems are in their growing season.

Peonies - Typically Late Spring (Around May) through early summer (Late June or July). Some of our incredible farmers in other climates do produce peonies at other times of year, though, so you may see them pop up on our site in other seasons. We know how beloved these stems are, so if we have them in stock we'll notify you via our marketing email or SMS channels. We have tips for working with fresh cut peonies here. 

Tulips - Tulips usually run from Late Fall into late Winter. Our insider tip for hyacinth, tulips, and other bulb flower is: if you see them growing in the ground outside, they're usually not available for florists any longer. 
Ranunculus - Fall through Early Spring (typically September through February or so).

Hydrangea - Late Spring through Summer, though transparently we don't use hydrangea particularly often because it's a very delicate stem. More info on working with fresh cut hydrangea can be found here. 

Lilies - Lilies are typically available year round, though we try to rotate the types of lilies we offer to keep things interesting for you. 

Roses - Roses are available year round! You will always find bouquets that include roses in our assortment. You can find tips for handling fresh cut roses here. 

Like any natural product, flowers have variations in their growing cycles and sometimes they defy our expectations in terms of availability! But no matter what the season is, we're always working to bring you the freshest and most beautiful flowers available.