HOW TO GROW RANUNCULUSES Experiments in growing these great flowering bulbs.

Of all the bulbs I've grown the ones that provide the longest, richest profusion of flowers, are the cheapest to buy, and the easiest to plant and grow are ranunculuses.

This page chronicles my experiments to find out the best way to grow and propagate these bulbs. (Actually, they are a tuberous root, though some people call them tubers. I'll use tubers on this page because it's easier to type.) After presenting some general cultural guidelines, this webpage consists of a series of questions about growing ranunculuses followed by the experiment used to answer each of them. Reading through these questions and answers should provide anyone a good idea of how to grow and propagate ranunculuses.

Here are some of the reasons I like ranunculuses:

They're cheap: I can get a bag of 40 tubers for 2 dollars at Wal-Mart. That's many times cheaper than almost any other bulb.

They are easy to plant: Unlike many bulbs that have to be planted 6 inches deep, ranunculuses only need to be placed 1-2 inches beneath the surface. This is a real back saver if you're planting a large bed.

Easy to grow: I've gotten great results just pushing the tubers into the soil with no special care. They're tough enough to survive light frosts, bright sun, mild dry spells and neglect.

Fast propagation: Bulbs like tulips, daffodils, and gladiolas only double or triple the number of bulbs that can be collected and made to flower the next season. It's not unusual to get eight new tubers from a single ranunculus in one year.

Early greenery: Planted in Fall, ranunculuses quickly sprout and provide winter-long greenery. Most other bulbs just sit in the ground without any top growth.

They provide one of the largest ranges of colors available in any bulb: As the pictures above and further down this page show.

The flowers are beautiful both in color and form.

The flowers resist frost damage so a late cold snap won't wipe out the bed.

They make great cut flowers: A ranunculus flower can last over a week after being cut.

 
With a list of advantages as long as this it makes good sense to plant ranunculuses, so shall we get started?

General Ranunculus Growing Techniques:

Plant the tubers, which look like bunches of miniature dried bananas, in Fall.

A typical ranunculus tuber. The cheap ones available
at Wal-Mart stores are small but still produce good results if
planted in Fall and allowed to grow all winter in a warm,
frost-free, sunny location.

In my high desert location I plant them against a south facing wall where they are protected from frost and get plenty of light. In locations with very hard frosts or snow they need to be planted in Spring. Ranunculuses prefer cool weather and full sun. Plant them 1 to 2 inches deep in average, well drained soil. (If the soil has standing water an hour after turning the sprinklers off they would do better in a faster draining location.) Fertilize with bulb food at planting time, when they start to flower, and once more when the flowering is over (to encourage the development of large and plentiful tubers.) Be careful to not let any of the fertilizer come in direct contact with the tubers or the foliage or it may burn them. Space small tubers three inches apart and very large ones, which may actually be a collection of several tubers tangled together, eight inches apart. (The first flowers appear around 1 March in my high desert location and the plants flower profusely for five to six weeks. Remove spent blooms to encourage a longer flowering time. Once the flowering is over, cut the flowering stems off as close to the plant as possible but don't trim any off the main foliage. The stems can be left on but it makes the plant look sloppy. Cutting the stems cleans up their appearance. Continue watering until the plants die back to the ground (usually 2 -3 months later) and then let the soil go dry. Avoid watering while the tubers are dormant or they may rot. The tubers can be left in the ground until Fall when they should sprout again. (Because they have multiplied, leaving them in the ground as is may result in crowding that could weaken the individual plants.) The tubers can also be dug, once the tops die back, separated, dried, and stored for planting later in the year. Digging them frees up the area for other plants and avoids problems with rot. It also allows you to divide and replant them at optimal spacing.

Those are the basics of ranunculus culture gleaned from my own experiences and reading through several sites about ranunculuses on the Internet. What follows are questions I had about ranunculuses and how I answered them.

 
Questiions and Answers:

I read on one webpage that ranunculuses do best in situations where the tuber is kept on the dry side while the roots are kept moist. Does this improve flower production or tuber growth?

Answer: I grew one patch of similar sized tubers in normal soil and another topped with quick-draining sand and compare the results. All other aspects of growth like planting depth, sunshine, water, and fertilization was the same. Plant size, number of flowers, size of flowers, and size of roots were the same for both groups so planting them in sand didn't make any difference in this test.

 
What is the best way to separate tubers?

Answer: I found that freshly dug ranunculus tubers are so fat with moisture that they're brittle and easily broken. Tearing them apart can severely damage them because their tangled roots are locked together. Letting them dry for a week before separating them is better, but by then, at least in my low humidity location, the tubers are so dry they are again brittle and easily broken, just like when they were too fresh. (Can't seem to win with these guys.) They safest time I found to pull them apart was after 24 to 48 hours of drying in a shaded location. At this time they still have enough moisture so that they bend a little instead of breaking yet have shrunk some so they are loose enough to divide. Individual clumps of tubers are easily identified within each cluster.

A freshly dug cluster of ranunculus tubers that started
off 9 months ago as a single small tuber.

Grab the main cluster with one hand and the clump to be pulled away with the other and with very small twisting and rocking motions ease the two apart. You'll be able to feel them twist relative to each other if they are going to come apart. If they feel locked solid I recommend leaving them as a single clump rather than risk damaging them.

 
Can large clusters be cut apart with a knife or forcibly ripped apart and still flower?

Answer: I cut or tore a couple of tubers in half and each piece grew fine. I suppose there's a limit, small tubers can't be divided down to individual fingers.

 
If an individual tuber (one miniature dried banana) is planted, will it grow?

Answer: I planted a dozen of these and not one of them sprouted so I'm concluding this does not work.

 
Do the tubers collected from one plant grow into plants that all have the same foliage shape and flower type?

Answer: Tubers collected in the Spring of 2005 were bagged so that only the tubers from one plant went into each bag. In Fall of 2005 I planted the contents of each bag in a solid group and marked each group so that the results could be tracked. Although frosts cause the foliage to take on a shredded appearance that makes determining differences a challenge, I would say that the foliage from tubers that came from the same plant is the same. In particular, one plant yielded four tubers that all produced the same variegated pattern of dark markings on their leaves. Flower colors and forms were also the same.

 
How many solid colors do ranunculuses come in?

Answer: The 2003-2004 planting of two different mixes produced nine different solid colors:

white
yellow
orange
red
a weird red (looked like it had some dark magenta in it)
light pink
medium pink
dark pink
purple

 
What happens if a very large cluster of tubers is planted as a single unit versus being separated and planted over a larger area?

Answer: I took two tubers that were the same size and planted one whole and the other divided into four pieces. They both produced about the same number of flowers but the divided bunch produced a more even, pleasing appearance and the plants were better able to support each other.

 
Does it help or hurt to soak ranunculus tubers in water before planting? How long should they be soaked?

Answer: Soaking in water for 14 hours caused one or two of the fingers in a large cluster to swell and split, the rest appeared unhurt. Wrapping clusters in a wet towel didn't cause any problems. I noticed that tubers rehydrated either way were much easier to handle and plant than dry tubers, which were brittle and tended to break. Soaked tubers aren't soggy, they are plump and firm. They all sprouted, grew and flowered about the same.

 
Do high priced jumbo ranunculus tubers grow larger and better than the small cheap tubers available in department stores?

Answer: Yes, but not much. The premium tubers I personally hand picked directly at a ranunculus farm averaged three times the size of the cheap ones from Wal-Mart. But once in the ground they performed about the same. The jumbo tubers produced plants that were 20 percent larger and had a few more flowers, but the difference wasn't worth the five-times increase in cost. I've read reports that the jumbo tubers should significantly out perform the smaller ones. Perhaps this was comparing tubers planted in Spring. With Fall planting the plants from the small tubers have enough time to catch up to their heavy-weight brothers. The germination rate (about 60 percent) was the same for both jumbo and small tubers.

 
How frost tolerant are ranunculuses?

Answer: In my high desert location (very clear, still, low humidity nights) I noticed that the plants can withstand temperatures down to 28 degrees with no damaged. At 25 degrees the tips of the leaves of a few plants will turn dark and shrivel, and at 22 degrees 1/4 of the plants will show some minor frost damage. However, they all quickly recovered.

On clear nights, which is typical where I live, plants can radiate heat away at night and actually become colder than the air. People living in cloudy, more humid locations my find that ranunculuses can survive lower air temperatures than mine can.

 
Do Ranunculuses produce seeds?

Answer: Yes!

If the flowers aren't cut off when the petals fall off, as shown above, in a few weeks the remaining seed head matures and dries out to look like this:

Each individual tuft is a seed seen edge on. Rub the pod between your fingers and the seeds tumble off byt the hundreds or even thousands.

Each seed is 1/8-inch across. The pointed end of the paper husk is what points outward from the pod, creating the pod's prickly look.

The question is weather these seeds will germinate. To answer this I'll be planting several hundred in the Fall of 2006. Check back around November and I post the results.

 
Fall, 2005, Planting Season:

The season started in October with preparing the bed. I decided it was time for a major overhaul so I worked 20 cubic feet of compressed peat moss, 100 pounds of alfalfa pellets, 55 pounds of kelp meal, 20 pounds of organic 5-5-5 fertilizer, and 15 pounds of bone meal into the top 16 inches of soil. This may have been too much because the bed heated up to 110 degrees from all that organic matter composting. After a week it cooled down and I was able to start planting.

Planting day this year was on October 30. The daily temperatures were averaging 72 degrees, calm, clear, with very bright sunlight. I used white sand to outline each planting area to help keep things straight for the many different experiments being conducted. Each area is filled with tubers harvested from one particular plant from last year's crop.

The weather remained warm and sunny and by 8 November, nine days later, the first sprouts appeared.

The planting map tells me that these are white ranunculuses.

Besides verifying that all the tubers from one of last year's rhizomes produce the same colored flowers, it'll also be interesting to see if they also produce the same type of foliage. Ranunculuses vary considerably in the type of leaf shape: some are potato-leafed, others are finely cut like celery leaves.

Here's what the bed looked like a month later on the first of December:

The germination rate is almost 100-percent. The only difference between this year and last, which only had a 60-percent germination rate, is that the peat moss added to the soil this year reduced it's PH from alkaline to slightly acidic. Perhaps ranunculuses prefer more acid conditions.

By the beginning of February the bed had filled in very nicely.

The plants are 9-inches tall, very full and dense. I'm getting a little concerned that they may be a little too crowded. Still, all the amendments added to the soil should provide enough nutrients to support them.

The leaves come in two main shapes:

what I can "potato-leafed" on the left and "celery-leafed" on the right. Variations part-way between these two forms are common.

On 1 March I spotted half a dozen good-sized buds. On March 12 the first flower, a red one, opened. For me the first ranunculus flower declares that Spring has officially started.

The bed hit its peak this year on April 15.

It provided one-hundred square feet of pure color for almost a month. By the first of May the flower count had dropped but due to cool weather late in the year, for my high-dessert location, the bed still looks good.

I always plant several dozen inexpensive, mixed bags of ranunculuses because while they may not be as good as the top of the line Tecolate varieties, they offer more variation of flower colors and shapes.

For example: this year I got both light and dark orange varieties...

...as well as light, open yellows and tight, darker yellows.

I mark the plants I like and save their roots for next year.

RANUNCULUS PICTURE GALLERY

Can't wait for Spring to see ranunculuses? Click on the thumbnails below to see larger images of the flowers. These will be added to and updated with better pictures (using my new Canon EOS 20D camera) as the 2005-2006 season gets started.

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