Sunflower – Helianthus annuus (common)
I started planting sunflowers because of the clay soil we started with. Sunflower roots can help break up and loosen heavy, compacted soils and with their help; along with compost and the materials I mulch with, I have made headway towards enriching the soils in our yard.
The state flower of Kansas is the bright & cheerful Sunflower. I’ve never personally seen a farm dedicated to them, but I do know that over the years they have become an important agricultural commodity. Sunflower seeds are rich in vitamins B1, A, D, F and they make a wonderful vegetable oil for cooking. I hear sprouts (especially from black sunflower seeds, the most delicious & nutritious ones) mix nicely with greens for tasty and nutritious salads. Sunflowers are an American plant, native to much of the Central US and southward to Central America, some Native Americans would make the seeds into a meal which was used for making gruel, cakes and drinks.
On average, depending on the variety, sunflowers range in size from 1½-10’ (sometimes up to 15’!) in height with an average 1-2’ spread. Also depending on variety, you may have plants with either single or multi-flowered heads. The color range available in sunflowers is enormous, a bright, happy yellow being the most common. A light lemon yellow or creamy yellow to near white are fun to come across. There are also orange, red (I really like the chestnut red, bronze & mahogany!) & bi-color, some with red & yellow tips…if that weren’t enough there are various shades of each of those.
They may seem like simple enough flowers, but up close the detail can sometimes amaze.
Most sunflowers are good for cut flowers, especially if you use a heavy or weighted vase… to keep it from toppling over, for the flower heads can be hefty at times! The wild ancestors which had flowers 2-3” wide, has become widely adapted and bred for much larger flower heads; sometimes around a foot across, those plants with the larger flowers need a richer, moist soil than many smaller varieties do. Flower heads typically consist of a circle of short yellow rays surrounding a brown central cushion of seeds; there are double flower varieties as well, such as my favorite furry, pompon like teddy bear which tops out around 1½’ H!
They are warm season annuals in all zones, though I hear there are some perennial varieties (Helianthus – maximilianii, multiflorus, salicifolius, orgyalis & tuberosus) I don’t believe I have any of those…unless of course my bird friends planted them for me… it has been known to happen!
Some sunflowers are touted as being nonallergenic, I think depends on whether or not the variety in question is pollen bearing or not. Because much of what I plant is for the birds and to draw in the bees and butterflies I don’t go looking for plants that might not provide for what they need.
If you are interested in adding them to your habitat… sow the large, easy to handle seeds in full sun during March; but be aware that slugs and snails will readily attack young plants cutting them off at ground level, you can protect them with slug bait or (my preference) a barrier of sharp grit (diatomaceous earth). Sunflowers grow rapidly and are difficult to transplant, (but not impossible) they will survive in average to poor soil; though, as I mentioned earlier, enriched soil produces the biggest flower heads. They are drought resistant with little need for extra feeding but you should keep the plants watered in long dry spells for best results.
Thin out weaker gangly stalks in April when they are about 6” tall, before they become the tough, widely adapted, coarse, hairy, sturdy plants that sometimes need staking. They can be a windbreak and screen when planted in a group, and as such, tend to support each other… otherwise you may need to start supplying support for some plants in May. They will flower with bold blooms through summer and fall, about June through September…maybe sometimes into October.
If planting in a container use multipurpose compost mixed with slow release fertilizer. I have heard that they are a soil improver; though I also hear they are thought to produce leaf substances to inhibit growth in some other species, possibly as a defense mechanism, inhibits nitrogen fixing bacteria in the soil. In any case, don’t plant them near pole beans, potatoes or grass; they are disliked by the pole bean & potato and they themselves dislike both grass and potato.
On the other hand they are liked by melons, cucumbers (for wind break and shade) and corn (protective to each other with reduced insects on each); as well as the bees (for pollen and nectar) and the birds who feed on the seeds from late summer thru winter. When you are growing plants for production purposes, for best results, always dig in plenty of compost to keep them from starving each other.