Bulb Persuasion

By definition, "forcing" something like a delicate little 'Tete-a-Tete' daffodil to bloom out of season sounds mean and heavy-handed. So, rather than "forcing" spring bulbs to bloom in pots indoors ahead of season, let me be kinder, gentler and call it bulb "persuasion". It's actually very easy and rewarding if you know the right procedure.

Bulb varieties that respond well to persuasion

Daffodils, tulips, crocus, hyacinths and the minor bulbs require a prolonged and uninterrupted chilling period of 38-45 degrees F. (called vernalization) for 10-12 weeks to trigger flowering. If you want to successfully capture that same stunning garden effect indoors you need to duplicate this chilling process. If you don't, you'll just have grassy leaves with little or no flower display to show for your efforts.

You should know there's a wealth of ways to achieve a gorgeous result. Some standard methods to persuade bulbs to flower indoors are:  

1. Pot the bulbs, sink the pot in the ground (to keep from freezing), cover with coarse mulch and pull out late winter to bring in and enjoy. Downside: Pots may be frozen in ground and inaccessible when you want them. Pots may be dirty and hard to clean.
2. Pot bulbs, put out in your cold frame. Downside: Seriously, how many of your neighbors have a cold frame or are going to build one for four or five pots of bulbs?
3. Pot, put in the refrigerator. Downside: Pots full of bulbs are space-consuming in the fridge, especially for the 10-12 week minimum needed for chilling. For those folks with a spare Frigidaire loafing in the garage this is a very workable solution.
4. Pot, put the watered bulb pots down in a window well and mulch lightly, with straw, for example. Upside: I've learned that window wells are a largely untapped garden resource, but you have to have access to them. Whether it's winter storage of evergreen bonsai or the aforementioned bulbs, wells are really useful. You're putting things below the frost line, temperature extremes are buffered, too, by the ambient heat from the house and they get natural precipitation (unless plastic dome-covered). Win-win, love it.

Who doesn't love having bulbs (especially hyacinths) in flower in February and March while the garden is still under siege? I readily admit to trying a number of different bulb persuasion techniques over the years and I have a favorite. It's my favorite because it gives consistent uniformity of flowers and no rotten bulbs. I call it the bag-in-the-fridge method.

Dated bags of bulbs ready for 10-12-week chill in fridge

Put the bulbs for persuading in paper, ventilated plastic or mesh bags so there is adequate air circulation around them. Remove ethylene gas-producing fresh fruit and vegetables from the fridge before putting the bags in the crisper. Ethylene adversely affects flower buds in the bulbs and can cause them to abort. If you're like me it's best to put a date on the bulbs so you know exactly when the chilling started. 8-10 weeks is the minimum, 10-12 is better. So, if you're looking forward to winter blooms get them chillin' as early as possible.

Prechilled hyacinth potted up and ready to please

With the bags-in-the-fridge method pull them out at the end of their chilling period and pot them. A standard houseplant potting mix is fine. Whether you use clay or plastic the pots must have drainage holes. Don't do less that six (more is better) daffodils or tulips per pot. Single, double early and Triumph are the best tulip classes for persuading. Because of their large bulb size the very tip of tulips and daffodils should be above the soil line. With their incredible fragrance 3-5 hyacinths per pot makes a wonderful show.

Water thoroughly and place in a cool (60-65 degree F. would be great), dark place in your home while the plants commence rooting. That will generally take several weeks. When green leaf tips start showing in the pot you can move them to more light and warmth. Strong light, if not direct sun, and cooler rooms will give you strong, stocky plants. When the buds start showing color move away from sun and heat to prolong flowering.

Persuading bulbs this winter? It's in the bag...

DIGGING DAHLIAS... LITERALLY

If you grow dahlias October's first frost presents a dilemma. Do you want to try and save the tuberous roots or does that seem like too much trouble? For those in the latter camp take heart. Gorgeous dahlias are inexpensive and a great value for the months of flowers they provide. So, don't feel guilty about tossing and buying new in spring from your favorite garden center or through dahlia specialists.

Try rolling your dahlia tubers in plastic this year!

For those that want to store dahlias it can be a challenging process. There are as many ways to store them as there are people growing them. So, I'm going on record that what I'm sharing is how I'm going to do mine this year. The digging and prep are going to be the same as in the past, but the plastic wrap storage method will be new for me.

The morning after a killing frost  (a freeze is more dangerous, making harvest a more urgent task) I like to get out and cut the blackening foliage back leaving only a 5-6" stem above the ground. This gives you a "handle" to use. Assuming daytime temperatures moderate after frost leave the plants in the ground for a week to "cure" before digging. This will put them in a state where eyes (next year's buds on the neck of the tubers) start swelling and (I'm told) the tubers will store better.

Keep big honkin' tuber mass intact when digging up

When you're ready to harvest dig with a spade or a fork starting at least 6-8" away from the stem. The single tuber you planted this spring will now be a big honkin' mass of tubers that you don't want to slice through. Dig all the way around, loosening the soil and lifting the plant gently. Don't pull it out by the stem!

Once you've lifted the root system from the ground many growers recommend gently washing soil off. Truthfully, I'm not crazy about the idea of wetting tubers, so I don't. I try to physically remove as much soil as possible with my hands (yep, it's tedious, but I don't have hundreds to do) without snapping off tubers. Then I turn them upside down on plastic in the garage (out of sun and wind) for a day to let the hollow stems drain. This also allows the tuber surfaces to dry and any remaining soil to be removed before storing. By the way, I personally omit a fungicide treatment, but you may want to do that before storage.

The "How do I physically store them?" part is where the process can go south in a hurry. The problem is keeping tubers from becoming too: wet, dry, hot or cold during the five or more months of winter storage indoors. As Charlie Brown used to say, "Arrrr-ggg-hhhhh." So, Tony is going to use the "plastic wrap method" of dahlia storage that I read about years ago, but never tried.

Separate tubers with "eyes", or buds, for next year

Lay down plastic, roll each tuber once, then add another

How is this going to work (fingers crossed)? Hopefully, I'm going to be able to see the little baby eyes swelling already this fall. I'll cut eye-bearing tubers from the clump. Remember, each tuber has to have an eye to grow next year. I'm going to get a long stretch of plastic wrap and lay it out flat. The first tuber is rolled until it is covered with one thickness of wrap. I'll place a second one in the fold of the first (not touching each other) and roll it over once, too. Then a third and maybe a fourth will be added all in the same stretch of wrap. I'll fold over the ends, secure with tape and write the variety name on the outside. Each variety will be a separate wrap group.

These will be placed in a box and I'll try to find a dark spot where the temps will stay between 40-50 F. Dahlias in storage don't want warmer or colder than that. I like the idea of the plastic wrap treatment since it:

* Takes less storage space
* Eliminates storage media (peat, sand, wood shavings, vermiculite) and whether it's too wet or dry
* You can see at a glance if any of the tubers are problematic in storage and need to be removed

So, dahlia enthusiasts, are you pitching or storing this fall?


              

It's Time to Plant Bulbs (Part II)

In the previous post I shared a bit of what's going on in spring flowering bulbs. This time I'd like to share more of the fun aspects of spring bulbs. Here are some bulb tips, tricks and factoids.

Shall we just own up? Honestly, don't you have at least one neighbor who is always doling out horticultural advice? Regardless of the fact that it's free and often unsolicited (let's not even start on accuracy) I'm not above suggesting a few ways to "one-up" the back fence garden guru.

* Consider a monochromatic color scheme, say white tulips. Measure the bed space and calculate how many tulips you're going to need. At 6" apart you'll need 4 bulbs per square foot. At 4" apart you'll need 9 bulbs per square foot (a knockout display, for sure).

ABC's of a longer bulb display

Let's say you have 10 square feet and you're going to do 6" spacing. That means you'll need forty-ish bulbs. Think about dividing into thirds. Get thirteen each of a white: early, midseason and late variety. Plant them in an ABC/ABC/ABC pattern. Guess what? That 10 square feet will be in bloom three times longer than if you had planted forty of one variety. The neighbors will be agog that your tulips are lasting so much longer than theirs.

* Here's a variation on that. Same bed- buy forty of the same variety. Plant 1/2 pointed up as conventional practice dictates. Place the remaining 1/2 on their side. Mother Nature is seldom fooled and "gravitropism" will kick in. The bulbs on their side will upright themselves, but be a week or so behind their correctly oriented counterpoints, essentially doubling the bloom time for the same space.

* Or you can do bulb "tiers" or "bouquets" as a colleague of mine calls them. Dig a hole 8" deep and a diameter of your choosing. Place something like large-cupped daffodils in the bottom. Cover with 2" of soil and then put tulips or hyacinths over that. Then you can add a third tier with crocus or the other minor bulbs 3" or so below the surface. You've just added multiple flowers to the same footprint and extended the bloom period.

Critters don't like these!

* If you have deer or rabbit issues there are a few bulbs that are naturally varmint resistant and will not be bothered by roaming livestock. Daffodils, fritillaria, scillas and hyacinthoides (not to be confused with hyacinths) are all distasteful to four-legged marauders.

The early spring blue "carpet"

* Have you ever noticed a spring lawn that seems to be "blooming blue" and wondered "What's that?" That's a very commonly asked spring question at our garden center and the answer is, "Scilla siberica, Siberian squill." Beautiful and multiplies like bunny rabbits.

* Know that a  new bulb planting may flower up to two weeks later than an established bed of the same variety, in exactly the same location. 

* A bulb planting, new or established, may bloom 7-10 days earlier on a south or west exposure than an east-facing site.

These tulips will last

* Daffodils are the peonies of the spring bulb garden. That is, they get better and fuller for many years after planting. Most (underline most) tulips are not as accommodating in that respect. If you want the longest years of garden service from tulips (called perennializing) consider the fosteriana, greigii, and Darwin Hybrid classes.

* Largest bulbs = largest flowers. True. Hyacinths are one case where bigger is not necessarily better. Topsize hyacinths will produce topsize flowers that will be so heavy they'll tend to list and topple, especially under heavy spring rains. Save the big hyacinth bulbs for indoor forcing, go down a size for garden beds.

* On the subject of hyacinths, people often react with a rash after handling the bulbs with bare hands. They have silica in the outer husk that can be very irritating. Simply wear gloves and avoid direct contact with your skin.

Give pink dafs a little shade

* Daffodils with any "pink" (term used loosely) flower parts should be situated in partial shade to prevent fading.

* Mice love crocus corms (bulbs). Birds, especially sparrows, may be attracted and peck at open crocus flowers, especially yellow. Please, don't even ask how I know that. Consider repellents for both.

Don't let your garden be the one on the block missing the soul of spring- the beautiful colors of Dutch bulbs!