Companion Planting Sunflowers

Companion Planting Sunflowers

I can’t look at a sunflower without smiling.There’s just something about that large yellow flower that reminds me of a happy face, and they also are very good for companion planting. Companion planting sunflowers add height, colour and they give an air of the dramatic to any plot.

There are 82 varieties of Sunflower and they  come in many sizes from dwarf (2ft) to giant (27ft) and varying colours from red, through deep orange to bright yellow. So there’s no reason not to include some of them in your plot design.

Companion Planting Sunflowers

Sunflowers attract ants, they move aphids onto sunflowers so the aphids will produce the sweet liquid honey dew that the ants feed on. So grow sunflowers as a sacrificial plant near any plants prone to aphid attack. Plants like :-

  • Beans
  • Tomatoes
  • Roses
  • Squash
  • Cucumbers
  • Melons
  • Lettuce

As sunflowers grow such strong, sturdy stalks, they can survive an aphid attack much easier than the plants they are protecting. The taller varieties are more suited to surviving aphid attacks as they are more robust.

The taller varieties also offer good shade for lettuce and other shade loving plants. Also squashes and melons will vine around the sunflower stalks thus saving space.

As sunflowers need plenty of nutrients to grow successfully it is advisable to leave approximately 2  square foot around each sunflower.

Sunflowers As Pollinator attractors

As the large flowers develop they attract Bees who come in search of nectar. These bees will then drift on to other plants in your garden to pollinate those as well.

Sunflowers And Sweetcorn

According to all the old gardeners that I’ve spoken to, growing sunflowers alongside sweetcorn will increase the sweetcorn yield and improve the flavour. The only problem I can see with this is that sweetcorn pollinate by the breeze and potentially the sunflowers could disrupt this process.

What Not To Plant With Sunflowers

Due to the allelopathic nature of sunflowers they will inhibit the germination of seeds so anything you grow with sunflowers should already be growing (plants not seeds). which is why you should never grow potatoes with sunflowers.
Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial (positive allelopathy) or detrimental (negative allelopathy) effects on the target organisms and the community.

Because of the allelopathic nature of sunflowers weeds will not grow too close to sunflowers. Beautiful flowers and a weed suppressant who wouldn’t want to grow sunflowers?

The Best Type Of Soil For Growing  Sunflowers

Sunflowers need plenty of nutrients to grow so add well rotted manure and /or compost to the soil before sowing/planting. So companion planting sunflowers means growing with other nutrient greedy plants like :-

  • Beans
  • Tomatoes
  • Cucumbers
  • Melons
  • Squash

Sunflowers need a lot of water but should not be waterlogged so well draining soil is best.

I also find it beneficial to use a heavy mulch to conserve moisture as sunflowers need a considerable amount of water to thrive. Using the buried pipe/ pop bottle to water the roots  as in my how to stop beans drying out post is also advisable.

That being said, they prefer full  sun and when they first flower the flower head will follow the suns direction across the sky. This will settle down once the plant is fully established.

The Best Month To Plant Sunflowers

As a general guide, sunflower seeds should be sown 2 weeks before the last expected frost for your area. In the UK this usually is towards the end of April until the end of May. Sowing times can be extended by 2-3 weeks if you sow indoors.

How Long Do Sunflowers Last?

If left growing sunflowers can last up to 6 weeks in bloom and then they become attractive seed heads. Once cut and put in vases of water they last from 5 to 12 days.

Do Sunflowers Come Back Every Year?

Some do, some don’t. There are 82 varieties of sunflower and approximately one third of these are perennial. Which means they will come back every year. The other two thirds are annuals and will die at the onset of winter.

What Are The Differences Between Perennial And Annual Sunflowers?

Apart from the fact that annuals only last one year and perennials come back each year. The main difference is that perennial sunflowers have smaller flower heads than annuals. Annuals will flower in their first and only year.

Whilst perennials don’t flower until at least year 2 and will flower year after year from then on.

What Time Of Year Do Sunflowers Bloom?

Sunflowers bloom from late Spring/early Summer until the first frost. With their prime showing being in mid Summer.

Do Sunflowers Bloom More Than Once?

The large annual sunflower grown for it’s showy flower and large seed head only blooms once. The perennial sunflower will keep on producing flowers throughout the growing season. As long as you dead head it regularly.

Dead heading is the process of removing dead flower heads to encourage new blooms to grow.

Growing Sunflowers As A Screen

You can hide your bins or fences with a row of sunflowers. These will make an attractive screen and if planted close enough together will make an effective wind break too.

Sunflowers And Staking

The taller growing varieties of sunflowers definitely need to be staked to support them through windy periods. These stakes can also be used to support runner beans or other vining plants. As long as they are grown as plants and not as seeds(see above).


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