Late Season Sunflowers – Can You Plant Sunflowers In Late Summer

Is it too late to enjoy sunflowers if you didn’t plant them in spring or early summer? Not at all. Click here for tips on planting late season sunflowers.

Sunflower in a field of sunflowers
(Image credit: Rehman Asad / Getty Images)

Beloved for their cheerful stature and edible seeds, sunflowers are among the most popular plants for the home garden. Though eager growers often choose to start their seeds as soon as all chances of frost have passed in spring, others may worry that the opportunity to grow their own magnificent blooms may have already passed them by. But, is it too late to plant sunflowers? How late can you plant sunflowers? In this guide, we’ll explore the “ins and outs” of sowing seeds, succession planting, and timing bloom for the longest display possible.

Best Times to Plant Your Sunflowers

Sunflowers can be started in a variety of ways. Though less common, seeds can be started indoors, in trays. This should be done no sooner than approximately 1-2 weeks before the last predicted frost date. After germination, gardeners can expect seedlings to sprout new leaves quickly, often outgrowing their trays and containers. It is for this reason that the second seed-starting method remains so popular: direct sowing. Seeds can be planted directly into weed-free, prepared beds once the soil has warmed and all chances of frost have passed.

The Latest You Can Plant Sunflowers Successfully

In order to best determine whether it is too late to plant sunflowers, growers should consider the required “days to maturity” as noted on their seed packet. Counting backwards from their average first frost date in fall, gardeners can gain some idea of whether or not there is sufficient time for plants to bloom. Type and cultivar planted will also play a role, as some may be better suited to late season growth than others. The best candidates are generally divided into one of two types: long-day and day-neutral.

Long-day types include more traditional, open-pollinated cultivars. As bloom is initiated by daylength, flowers of this kind will bloom at roughly the same time, regardless of when the seed was planted. Newer, day-neutral hybrids will bloom regardless of daylength, with most maturing in as little as 60 days. This characteristic allows gardeners greater flexibility in terms of planting, with many finding luck with succession sowing.

A hand holds three sunflower seeds over a pot labelled sunflower

(Image credit: Richard Clark / Getty Images)

What are the Risks of Planting Sunflowers Later?

Though it is possible to plant sunflowers late in the season, it is not without risk. Seeds sown beyond midsummer may struggle to establish themselves, often succumbing to the overgrowth of weeds or insect troubles. Those set to bloom as conditions begin to cool in late summer may also suffer as overall growth begins to slow. Plants maturing at this time are likely to produce smaller-than-usual flowers and will often demonstrate poor seed set.

Best Sunflowers for Growing Later

  • ‘Autumn Beauty’ Sunflowers - A tall, branching variety, ‘Autumn Beauty’ flowers in an attractive array of yellow, orange, and burgundy tones. Long stems make the flower ideal for use in cut arrangements, or mixed borders. Gardeners can expect plants to bloom approximately 75-85 days from planting.
  • ‘ProCut Series’ Sunflowers - Bred specifically for cut flower production, day-neutral blooms open uniformly, 50-60 days from planting. Single-stem flowers within the series are available to growers in a wide range of colors, which include pale yellow, orange, red, and bi-color types.
  • ‘Teddy Bear’ Sunflowers - ‘Teddy Bear’ sunflowers are celebrated for both their unique flower form and dwarf habit. Small plants grow quickly, maturing in as little as 65 days. Blooms open to reveal fully double, butter-yellow petals, and are ideal for use in pots and containers.

Frequently Asked Questions

Can You Plant Sunflowers in July?

In most regions, sunflowers can be successfully planted in July. Those hoping to do so may see the best results with the selection of early-maturing or day neutral types. This will allow ample time for growth and the production of blooms before cooler arrives in late summer and fall.

How Late Can I Plant Sunflowers?

Determining how late sunflowers can be planted will vary by zone. While those living in warmer regions may be able to sow seeds throughout summer, gardeners elsewhere may be much more limited by their growing season.

Which Sunflowers Should Be Planted Early?

Annual sunflowers, regardless of type, can be planted into the garden as soon as all chances of frost have passed in spring. Some cultivars, however, will benefit from early planting more than others. This includes those that grow to be especially tall or are valued for their oil content and seed production.

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Tonya Barnett

Tonya Barnett has been gardening for 13 years. Flowers are her passion. She has transformed her backyard into a cut flower garden, which she regularly chronicles on her YouTube channel