When Perennials Bloom: An Almanac For Planning and Planting by Tomasz Anisko is a very useful reference book for the sequence of perennial flowering times. As well as the length and dates of the bloom intervals in a number of zones, it contains a great deal of information about plant culture. I bought this book last summer, and I appreciate it as a handy reference, a delightful bedside read, and a great picture book for winter dreaming.
Knowing the relative flowering dates for perennials is extremely useful when planning your garden. This book will help you coordinate those times, to spread them over the year, fill in the gaps, or go for a massive display in one season.
The bloom dates are especially detailed for zone 6 of Pennsylvania, the location of Longwood Gardens, where the author is the curator of plants. However, the flowering times of other regions are also included. I found the Moscow ones more practical for my specific zone. Even if you are not in an explicitly mentioned gardening zone, it is still helpful to know the relative sequence and length of the flowering period for the perennials.
The middle picture shows a sample of a quarter of a page, showing the detailed information about the flowering times for Brunnera. It is even broken down into differences between the species and a cultivar.
Besides the individual bloom charts for each perennial, at the back of the book is a particularly useful composite chart. This includes horizontal bars of the flowering months for hundreds of perennials, arranged in order from earliest to latest. The length of the shaded bars on the chart is an easy visual to find long lasting flowers that will carry the garden along, as the shorter flowering perennials come and go. These seven pages are great for a comprehensive understanding of the timing of each perennial’s flowering season.
Although the perennials in my zone 3 garden have different months for flowering than the chart, it is still applicable. My garden season is compressed, but the sequence is still the same. By looking at perennials I currently grow, and when they bloom, it is easy to compare. Because bloom duration can vary from year to year, the data is colour-coded to show the most common dates, as well as the range of early and late intervals for each plant.
By looking down any column of the charts, you can quickly discover plants that will be likely to bloom at the same time. This is valuable for creating or redoing a garden bed, when you are trying to coordinate the flowers to bloom together.
You can also plan a bed to flower across the gardening seasons as you look from the beginning to end of the list. My beds are heavy on the spring flowering plants, since I look forward to their blooms, after a long winter. However, sometimes a garden seems bare in certain months, and you are looking for flowers to perk it up then.
I’ve been keeping a simplified version of a flowering chart for my garden. Here is a previous post, showing how you can keep track of the bloom time of your perennials. It includes a sample of the beginning of one of my charts.
As well as the detailed lists of flowering dates, the book also includes lots of beautifully coloured photos, showcasing the plants and their flowers. There are thorough descriptions of the perennial flowers and foliage to accompany the pictures, including information about cultivars and varieties.
It is also a detailed reference of other background information for each perennial, such as the origin and natural habitat of the plants, which I find helpful for figuring out where they might do well in the garden. The tips on plant culture for each entry are comprehensive and practical, including water, light and soil requirements, cutting back, and siting. Most entries include zone hardiness as well. Of course, an entry like, “hardy to zone 5, possibly zone 3,” is just too tempting for me. :)
At 510 pages, When Perennials Bloom, from Timber Press, is packed with valuable information, so you can use it as a reference to research specific plants and their care, to help coordinate the flowering times in your garden, or as an enjoyable read.