Using Florel Effectively By Roger C. Styer

Once timing, application rate and crop susceptibility are understood, Florel can be an effective tool for both controlling height and promoting branching.

With more and more new vegetative annuals being produced,growers are finding themselves doing more pinching and cutting back tostimulate better branching and to control growth. Many of the new vegetativeannuals are quite vigorous and designed for use in larger containers. However,growers are also producing them for individual sale in smaller pots as well asmixed planters. Whether you buy rooted or unrooted cuttings, the problems arethe same — get plants to branch early to fill out the pots faster and controlthe growth late.

Why Use Florel

If you have not worked a lot with Florel, you really need tostart if you plan to grow vegetative annuals profitably. Florel is anethylene-producing chemical that increases branching, takes off early flowerbuds in many crops and acts as a growth regulator. By spraying with Florelearly, either during propagation or shortly after potting, you can get fasterbranching without pinching or with less pinching. Some growers will still pinchcuttings if the height is already too tall.

For most crops, spraying with Florel will also take offearly flowers and delay subsequent flowering for a period of time. Forgeraniums, this re-blooming time can be 6-8 weeks, whereas verbena and lantanamay rebloom in 2-3 weeks. Florel will not abort flower buds on some crops, suchas mums, but will delay flowering if flower buds are not already evident.Disbudding may be needed during propagation with crops such as New Guineaimpatiens to reduce Botrytis problems.

Florel also acts as an early growth regulator, although notin the same manner as other chemicals such as B-Nine, Bonzi or A-Rest. And,best of all, the cost of Florel is cheaper than other growth regulators anddefinitely more cost-effective than pinching or cutting by hand.

You can use Florel in stock production, during propagationor after potting. If you produce your own stock plants, spray Florel either inplace of pinching or around the same time to increase the number of cuttings.Á Stop spraying Florel at least two weeks before you want to takecuttings, so you do not have a carry-over effect into propagation, which willdelay rooting or cause more leaf-yellowing immediately after sticking.

In propagation, wait until you have some rooting and areweaning plants off mist before using Florel. Generally, spray Florel one weekbefore potting to increase branching. If you want to take off early flowers inpropagation, spray earlier but at a lower rate. After potting, wait untilcuttings are rooting out into the new media before spraying with Florel. Thatmeans Florel can be applied about 1-2 weeks after potting and can be repeated1-2 weeks later if needed. It may take a week to show the branching effects ofFlorel, so be careful about applying too frequently and getting too mucheffect. Many growers like to spray hanging baskets while on the bench or ground1-2 times before hanging. Keep good notes on re-blooming times for differentvarieties in order to determine cut-off dates for using Florel.

How To Use Florel

Many growers have tried using Florel and found it doesn’twork very well for them, while other growers have had excellent results on thesame type of plants. Why? I have found growers do not know the key points forhow to best use Florel. Here’s what you need to know:

pH. The water in thespray tank after adding Florel should have a pH of 4.0-4.5. If you have highalkalinity in your water, you may need to add a buffering agent such as pHase5or acid to lower water pH enough. Remember, Florel itself will lower water pHsomewhat, so be careful about getting too low (pH 3.0), as you can burn plants.Growers with very pure water may need to add a buffering agent that willactually keep water pH from getting too low. Activity of Florel is greatlyreduced if water pH is not correct.

Concentration. Useconcentrations of 250-500 ppm for most plants. Normally, start with 500 ppm andsee what kind of reaction you get. If too strong, reduce to 250 ppm. Sensitivecrops such as any impatiens, bougainvillea and maybe some fuchsia should besprayed with 250 ppm to start.

Timing. Use spraysolution within 2-3 hours after making up, and do not hold overnight.

Application. Spraylike B-Nine to run-off. You need to get coverage on all leaves and stems.Florel is not active in the soil through the Á roots. Leaves need tostay wet with Florel for 3-4 hours to get most of the chemical into the plant.Drying off too fast will reduce effectiveness and require a higher ppm or morefrequent spraying. Select proper time of day to do Florel spraying.

Repetition. Watchrepeated usage and determine re-blooming times. Crops such as verbena andlantana will need more applications of Florel and will re-bloom within threeweeks, whereas geraniums may only need one application and take 6-8 weeks tore-bloom.

Special Circumstances.Avoid spraying plants when under stress — not your stress, but the stressthe plants are being grown under! Florel is a stress-exaggerator, which meansit will turn leaves yellow or cause them to drop if plants are under stress.Make sure plants are watered properly and shade is closed before spraying. Waitfor roots to come out first on a cutting or liner just planted.

Crops That Respond to Florel

The list of crops that respond to Florel can be quite long.I tell growers that any crop you feel needs pinching for better branching is anautomatic candidate for Florel. A lot of work has been done by Dr. PeterKonjoian with different crops in an effort to get the label expanded. Much ofthe work by growers may be off-label, but it works. Table 1, above, contains alist of crops that respond to Florel, but by no means is this listall-inclusive. You need to experiment with Florel on other crops and keep goodnotes.

Florel works best on geraniums and other vegetative annualsthat need a pinch to branch better. You can produce fuchsia baskets with 2-3sprays of Florel and no pinching, and get a full-looking product. Ivy geraniumsfill out hanging baskets with 1-2 sprays of Florel and may only need a pinch onoverly long laterals. Bougainvillea will branch better with Florel but may dropleaves due to stress. Be patient, leaves will re-sprout at most of the nodes.

Florel works very well on herbs — getting them tobranch without pinching and acting as a safe growth regulator. However, herbsare not on the label. Some growers are trying Florel on vegetables, but youneed to watch how much drought stress you are using or your tomato plants willturn yellow overnight.

Garden mums were one of the first crops Florel was used oneffectively, but many growers are no longer using Florel on mums. This isprimarily due to the newer varieties being better-branching with or withoutpinching, and Florel has a tendency to delay flowering on some varieties evenwhen used near the pinch.

On poinsettias, Florel can be used five days before andafter the pinch to bring all the breaks out more uniformly. This will changethe finished shape of ‘Winter Rose’ so all of the blooms are held at thetop, not the staggered look that consumers seem to prefer. If you have good-qualitycuttings that take off well after potting, you may not see any benefit onbranching with Florel, just a growth regulator effect. The jury is still outabout if Florel is really needed on poinsettias.

Using Florel on stock plants and during propagation canremove or abort early flowers on many cuttings. Be careful about rates andtiming to avoid too much stress or effect. In propagation, use 250 ppm toremove early blooms on New Guinea impatiens, double impatiens and other crops.Do your own trials and keep good records.

When the weather is really warm (greater than 90° F),you may need to reduce rates to avoid creating more stress on plants. Withlower rates, you can spray weekly if needed. Poinsettias grown under high temperaturesmay need rates as high as 1,000-1,200 ppm to get an effect on branching.Remember, when using Florel, reduce your usage of other growth regulatorsduring that period.

Here’s the bottom line on Florel: Use it on a wide range ofplants to promote branching, remember how Florel works and do your own trials.Once you learn how to use Florel effectively, you’ll wonder how you ever didwithout it.

Roger C. Styer

Dr. Roger C. Styer is president of Styer's Horticultural Consulting, Inc., Batavia, Ill. He can be reached by phone at (630) 208-0542, fax at (630) 208-0966 or E-mail at [email protected]

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