Sunflower Growing Tips: Single-Stem vs. Branching

I'm here today in our sunflower trial, and I'm going to go over a few basic growing tips for sunflowers. I'll talk a little bit about single stem varieties and also branching varieties and some differences in growing both of those.

Seeding Sunflowers

First of all, to start, sunflowers are a great crop for direct seeding, so the seeds are large and they germinate quite quickly. They're a good option for a direct seeded planting. A couple of things to consider, though, is that they are frost sensitive. You want to wait until after your last frost in the spring to start seeding them and then also you can wait until the soil reaches 55 to 60 degrees as well. They might germinate in cooler soil, but it might be a little bit slower.

Those are a couple of things to consider for seeding. It is possible to transplant sunflowers, however, because the seed germinates quickly and the seedlings develop fast in the trays, they do have a tendency to stretch or become root bound if you're not able to get them into the field right when they need to go in. If they do become stressed in the trays or root bound, that can affect the bloom quality later on in the season. We recommend direct seeding. Although again, it is possible to transplant, you need to be very mindful of when you're putting those seedlings in the ground.

Branching Sunflowers

I'll talk a little bit about branching sunflowers first. I'm standing in front of a branching variety right here. Branching sunflowers are great in that they produce multiple blooms or stems per plant. You can get multiple cuts off of a single plant of a branching sunflower. They tend to have a wider flowering window. Because they're producing multiple blooms on a single plant, they'll they tend to open over a wider range.

You can enjoy them for longer. There is a lot of diversity in color and bloom, size and plant height within branching sunflowers. There's a lot of different options depending on what you're looking for. Branching sunflowers are because of their long flowering window and because you can get multiple stems or cuts per plant, they can be a really good option for a home-cutting garden for beautification or landscape.

They can also be great for u-pick operations as well. You might see a little bit more variability in branching sunflowers than you might in some of the single stem varieties. But again, there's a lot of productivity on these and a long flowering window, which makes them a really nice option.

Pinching Branching Sunflowers

In terms of care for branching sunflowers. One of the things that we do in our trials and recommend is pinching branching sunflowers. What this does, when the plants are 12 to 18 inches tall, we remove the very center of the plant. This encourages the side stems to branch and stretch a little bit longer.

It helps balance the plants out and it ensures that you'll get a nice long side stems and that are probably better suited for cutting. If you don't choose to pinch your branching sunflowers, they will still branch even if you don't pinch them. But what they will tend to do is, if they're left unpinched, they'll typically produce one large flower at the top of the plant, surrounded by several smaller, shorter side stems. You maybe won't see as much length off of those side branches if you don't pinch your branching sunflowers.

Again, pinching helps to balance out the plant. It helps to balance, encourage more even growth of all of those side shoots. Ultimately you'll get more usable stems off of them. One other thing to note about if you're going to pinch them is that it will delay flowering a little bit, usually a week to ten days later than if you were to leave them unpinched.

Spacing Branching Sunflowers

One other thing to consider about branching sunflowers is your spacing. Because these plants they're branching, they take up a lot of space. You can hopefully see from these plants behind me that you know how wide they can get. We have these spaced at 12 inches between plants. But really you could go wider than that. I would say 12 inches between plants is probably the minimum. 18 to 24 inches between plants is also a good spacing and it can give a little bit more room.

There is diversity in the plant habit of branching sunflower varieties. Varieties that do tend to be a little bit more compact branching could go with a tighter spacing like 12 inches, whereas some of the really large ones you would want to give 24 inches. That just takes a little bit of understanding of the varieties that you're growing.

But again, a wider spacing, 12 to 24 inches on branching sunflowers helps to keep them less crowded and make sure that you can get access to all of the stems as they're developing.

Single Stem Sunflowers

I'm here in front of a stand of single stem sunflowers, and I'm going to talk a little bit about some things to consider if you're growing these for cut flowers. Single stem sunflowers are different from branching varieties in that they only produce one flower per stem. You have a nice tall straight stem, but you'll only get one flower off of these plants.

Do Not Pinch Single Stem Sunflowers

One thing that's important to remember about single stem sunflowers is that you do not want to pinch these varieties. If you pinch these varieties, you will not get a bloom. That's a big difference between the branching and the single stem varieties.

Spacing Single Stem Sunflowers

Another difference is the amount of space that they take up in a field or growing area. Again, because these are just producing one bloom on one tall straight stem, they will take up a little bit less space than a branching variety that has multiple stems coming off of the same plant. That's where your spacing becomes important for single stem varieties. They can be packed in much more closely. We space ours here four inches apart within the row. Spacing is also one of the ways that you can manipulate the bloom size on single stem varieties.

If you are looking for a larger bloom on single stem varieties, space them wider apart have a less dense planting. Whereas if you're looking for a smaller bloom size and a thinner stem, spacing them tighter and closer together will have that effect. It will cause the bloom size to be a little bit smaller. There are other things that affect bloom size in single stem sunflowers. Things like day length and light and fertility will affect the bloom size in addition to the planting density. But the planting density is one of the ways to really control or dial in the size of your single stem sunflowers. They're very responsive to planting density.

I have here an example. This is the same variety. The one on my left was grown at a tighter spacing and then the one on the right had a wider spacing. You can see the difference in bloom size here on the same variety, just slightly different spacing. That's something that the single stem varieties are more responsive to than the branching varieties. Something to consider as you're planning your plantings.

Harvest Window

Another thing to consider or the way that the single stem varieties differ from the branching varieties, is that single stem varieties are developed typically for commercial cut flower production. One of the characteristics that's helpful in that is having all the plants within a variety bloom in the relatively short window, really ideally within a couple of days of each other.

This helps make harvesting much more efficient if all the varieties are blooming and harvestable at the same time. If you are growing a single stem variety, you will probably see a much narrower flowering window than you would see for a branching variety. A branching variety will give you color over a longer period of time. A single stem variety is going to probably bloom pretty quickly, all the plants in that planting. Again, depending on what are you using them for, that's something to consider.

When to Harvest

One other thing to note about single stem sunflowers and sunflowers in general is the harvest stage. You can harvest sunflowers as soon as the first ray petals are beginning to unfurl on the disk. This is a a good example of that right here.

You can see there's a little bit of color and the first ray petals are just starting to unfold. That's the stage you would harvest at if you were looking for the maximum vase life. It is certainly possible to harvest at a later more open stage. However, the longer you wait, the shorter the vase life is going to be after you harvest. Again, this is an example of ideal harvest stage for single stem or branching sunflowers, but you can definitely harvest later.

Succession Planting

Another thing to consider when planting sunflowers, especially single stem varieties, is succession planting. Because single stem varieties do tend to bloom in a very short period, if you want to have a long sunflower season, you are going to want to succession plant. There are a couple of different ways that you can do that. One is to pick your one or two favorite varieties and seed them every 7 to 10 days over the course of your season. That will help you get a pretty consistent season of sunflowers. Another way that you could succession plant is to choose several varieties with different maturity dates. Some that mature earlier or some that mature a little bit later and plant them all at the same time. Then you can harvest from them from that single seeding as the varieties mature.

We have a lot of more in-depth information on succession planning for sunflowers in online suflower succession planting program, please check that out if you're interested in that.

But again, for single stem sunflowers, succession planting is a really good option for extending your sunflower season. For branching sunflower varieties, because they do tend to have a longer flowering window, if you want to extend your season with branching varieties, usually just two or three seedings, several like 2 to 4 weeks apart, depending on the variety, will help extend your season with the branching sunflowers. But again you get a longer bloom window on those anyway just because they are producing multiple flowers per plant.

Pollen Producing vs. Pollenless

One other thing to consider when choosing sunflower varieties is whether they are pollen producing or pollen less so all single stem hybrid varieties are pollenless; they do not produce pollen. And this can be beneficial because pollen can stain furniture and clothes and tablecloths and things. That can be a problem depending on what the end use of your sunflowers, where they're going and who's going to be using them.

With pollenless varieties, you do not have to worry about that pollen shedding and causing problems later on for the end user. Many branching varieties are also pollenless, although you're more likely to find pollen producing varieties in the branching sunflower category.

The varieties in my right hand produce pollen. One of the ways that you can tell: it should be pretty obvious as the blooms open, which ones are pollen producing or not, because the pollen producing blooms will have of fine gold dust on the anthers as the disks start to open up and you'll be able to see the pollen pretty clearly.

For varieties that are not pollen producing, like the two in my left hand, these varieties, as the disks open up, there won't be any pollen at the center of the blooms; there will just be that dark black without any dusting of gold or orange from the pollen.

One thing to note about pollen with sunflower varieties as well as that, even though they're not producing pollen, they are still producing nectar. That nectar can be a food source for insects and for things like bees and butterflies. Even though they're not producing pollen, there still is a source of food in the nectar from these blooms. We will often see bees and other other insects flying around and feeding on our pollenless sunflowers. However, varieties that produce both pollen and nectar do provide more of a complete food source for insects. If you are looking to establish insect habitats or support bee populations, then choosing varieties that do produce pollen will help provide a more complete food source.

Again, you can find all of that information on varieties you're interested in, on our website or in our catalog. Thank you for watching. I hope that this is helpful in as you're considering what sunflower varieties to grow.