When To Plant Annual, Perennial, and Biennial Flowers From Seeds

Question from Brandon:
Please help! My wife and I, as inspired by your book, are setting in motion our plan to start our fall planting by starting seed in August. We’re planning our beds for cool season flowers, but we are having a giant disagreement about warm season blooms. Here’s the question: When should we plant rudbeckia, shasta daisies, conefower or other warm-season perrenials? What I’ve learned from your book says May, my wife says October. We live in Beaumont, CA which is inland. In order to draw up our plans, we need to know when to plant them.

We’ve basically followed your book for our lawn and our roses since last october – to spectacular results, and we’re setting our sights on our annuals and perrenials this year with your help. Thanks in advance for your expertise.

Answer from Pat:
Even though you live in Beaumont, California, at the foot of the San Bernadino Mountains, you are still living in a Mediterranean climate with a relatively mild winter. It just happens to be somewhat cooler in winter and hotter in summer than ours along the coast. And regarding your disagreement on when to plant seeds, luckily, both you and your wife are partially right. Also, it’s a complicated subject and I’m glad to have the chance to at least try to set it straight, including the cool- and warm-season annuals and biennials (just in case this helps.)

To begin with your question: To plant most conventional, summer-blooming, bedding perennials from seeds in flats and then pots, cold frames, or the ground, one needs to begin a full year in advance. This is not an easy task and it takes over a year of work and care but can be done and is hugely rewarding when it works. (See page 246 for basic instructions.) June is the time for starting seeds of perennials along the coast and April or May inland. This means that if you wish to grow your own plants of such items as Shasta daisies and the best rudbeckias, to bloom next year, it’s none too late to start. But for the wilder types of Rudbeckia and gaillardia and ratibida—even Echinacea purpurea, all things that are more like wildflowers, fall planting is fine, especially if you are planting in the ground right where you want to grow them.

But though all of the old types of conventional bedding perennials have to be planted a whole year ahead in order to have plants that will bloom the following summer—and here is the tricky bit that makes you both right—some of the new improved, more compact perennials can be planted from seeds in spring, and still give you flowers the same summer. (Read the seed packages; some new varieties are also described online.)

You didn’t ask about planting seeds of annuals and biennials, but right now in July is the best time for starting biennials such as foxgloves, sweet William, Canterbury bell, and cup-and-saucer from seeds. By starting now, you will have little plants ready to plant out into beds in October and they will bloom next spring. Protect tender plants from frost, and please see page 265 in my book for a discussion of biennials from seeds.

And next month, in August, (page 297) is the time for planting fall and winter-blooming annual flowers from seeds. A lady I knew years ago who lived in an interior climate zone like yours always planted such winter annuals as dianthus, stock, schizanthus, and Nemesia strumosa in flats from seeds August, and she had loads of bedding plants with which to fill beds at low cost in October to bloom for winter and spring bloom. She also planted ranunculus and her garden simply overflowed with color. To get an idea of what will work, look around to see what flowers do well in other gardens at various times of year and then count the months backwards and read the seed catalogues for days from seed until bloom to find when to plant.

Now for summer items: In your climate zone (if you were planting summer annuals from seeds), plant them under lights or indoors early enough so you can put them out in the garden after spring flowers fade. But in my climate zone (coastal) I plant seeds of warm-season annuals (things like zinnias, red salvias, and marigolds) straight in garden beds after the weather warms up in May. The important point is that if you were plant most perennials from seeds that late (i.e.: in May) they won’t bloom until a whole year later, but some new varieties will do so.

Three years ago I planted seeds of Gaillardia ‘Arizona Sun’ in fall along with some spring-blooming wildflowers. By spring, the wildflowers which had bloomed earlier were finished and I pulled them out. I then had a bed full of Gaillardia ‘Arizona Sun’, and they began blooming as soon as the spring flowers were finished, but when I pulled out the other flowers it had left a few gaps. I still had some Arizona Sun seeds so I popped them into the gaps. The later-planted gaillardias grew more rapidly in warmer weather, but ended up much smaller and not nearly as floriferous as the ones I’d put in earlier. Thus, though spring planting will work with any of the brand new perennials designed to bloom the first year, I would stick to fall planting. You don’t really have to begin as early as August except (as explained above) for the bedding plants of winter annuals and for biennials.

One last comment: I had another friend in an interior climate zone whose garden got frost every night in winter, who liked planting from seeds like I do right where the plant is to grow. She planted all her annuals and perennials, cool-season and warm-season ones at the same time in October. She did not get a lot of winter bloom as I do, but she said that her little plants got pinched back by frost and if anything it was a benefit since they were compact and sturdy and she didn’t need to stake them as I’ve always needed to do.