October 2007 Culture

Achillea millefolium Tutti Frutti Series By Paul Pilon

With its ease of production and first-year flowering, the Tutti Frutti series is a great addition to commercial perennial programs. Other commercially beneficial attributes include uniform flowering, a long bloom time, great plant habit for container production, and robust disease-resistant foliage. The Tutti Frutti cultivars produce an abundant supply of large, colorful corymbs held on sturdy, compact stems. This series is considered self-reliant and maintenance free. The Tutti Frutti cultivars were selected by Sahin in the Netherlands. With their attributes, they will definitely catch the eyes of commercial growers, landscapers and gardeners across North America.

In the landscape, achillea grows best under full sun and in locations with infertile, well-drained soils. The Tutti Frutti series is hardy in USDA Hardiness Zones 4-8 and AHS Heat Zones 9-1. They are heat-loving plants with foliage that does not melt down during hot, sticky weather. Apricot Delight and Wonderful Wampee reach 22 inches tall and spread to 22 inches at maturity. Pink Grapefruit and Pomegranate reach 29 inches in height and 28 inches in width. They naturally bloom for an extended period (June to August), and the bloom time can be extended if the plants are dead-headed. Achillea are commonly used to attract butterflies into the garden, as accent plants, as fresh cut flowers or as cut dried flowers for use as everlastings.

Propagation

The Tutti Frutti cultivars are vegetatively propagated from tip cuttings by licensed propagators. A U.S. Plant Patent has been applied for (USPPAF) and propagation without permission of the applicant is illegal.

Growers receiving unrooted cuttings should moisten the rooting medium in the plug flat prior to sticking the cuttings. The Tutti Frutti series does not require rooting compounds. Place the cuttings under a low misting regime for about the first 7-10 days of propagation. When possible, it is usually best to propagate under high humidity levels (90 percent relative humidity) with minimal misting. It is beneficial to begin constant liquid feeding with 75- to 100-ppm nitrogen at each irrigation beginning 10 days from sticking.

The misting can gradually be reduced as the cuttings form callus and root primordia. The cuttings are very susceptible to rots during propagation and the misting frequency should be kept to a minimum. Remove the cuttings immediately from the mist once they are rooted. The cuttings are usually rooted in less than 3-4 weeks with soil temperatures at 68-74¡ F.

Production

The Tutti Frutti cultivars are well suited for production in 1-quart to 1-gal. containers. They perform best when grown in a moist, well-drained growing mix. Many commercially available peat- or bark-based growing mixes work well provided there is good water holding ability and adequate drainage. Irrigate as needed when the plants are young and becoming established. Once the plants are large, they will require more frequent irrigations as they will dry out slightly faster. Overall, it is best to grow them on the slightly dry side but not to the point of wilting. When irrigation is needed, water them thoroughly, ensuring the entire growing medium is wet or nearly saturated.

Yarrow is a light to moderate feeder and performs best when the pH is kept at 5.8-6.4. To avoid excessive stretching, growers should maintain "lean" nutritional programs. Growers using water-soluble fertilizers commonly apply 50- to 75-ppm nitrogen with every irrigation or use 150 ppm as needed. Controlled-release fertilizers are commonly incorporated into the growing medium prior to planting at a rate equivalent to 0.75-1.0 lbs. of elemental nitrogen per yard of growing medium. Plants grown under high fertility regimes generally become very lush (leggy) and may take longer to flower.

With its compact habit, controlling plant height is not usually necessary when producing the Tutti Frutti series. Providing adequate spacing between the plants will reduce plant stretch caused by competition. If controlling plant height is necessary, several of the commercially available PGRs are effective at controlling plant height when they are applied using the appropriate rates, frequency and timing. In the northern United States, applications of B-Nine (daminozide) at 2,500 ppm or the tank mixture of B-Nine at 2000-ppm and Sumagic (uniconazole) at 3 ppm have shown satisfactory control of plant height when multiple applications were made.

Insects and Diseases

Although achillea can be produced relatively insect free, aphids, slugs, spider mites and thrips often become a problem. Of these pests, aphids are the most prevalent. Several growers implement proactive aphid control strategies using monthly spray applications of systemic chemicals containing the active ingredients acetamiprid, dinotefuran, imidacloprid, pymetrozine, thiamethoxam or using the labeled rates for each of these products. Growers producing achillea in outside production sites are likely to observe caterpillars, leafhoppers, Oriental beetles and spittle bugs feeding on their crops. These pests can be detected with routine crop monitoring; control strategies may not be necessary unless the scouting activities indicate actions should be taken.

The most common diseases observed attacking achillea are powdery mildew, Rhizoctonia crown and root rot, rust and Sclerotium stem rot. Of these diseases, powdery mildew and Rhizoctonia are the most prevalent. To control powdery mildew, it is best to manage the environment by providing the proper plant spacing, adequate air movement and controlling humidity. If desired, growers can also follow a preventative spray program using the appropriate chemicals. I have observed good results when rotating products containing the active ingredients azoxystrobin, piperalin, potassium bicarbonate, triadimefon, trifloxystrobin and triflumizole with my preventative powdery mildew programs. Achillea is most susceptible to Rhizoctonia when they are over-watered. With good watering practices and adequate air circulation, the occurrence of most diseases can almost be negated.

Forcing

The achillea Tutti Frutti series can be easily forced into bloom any time of the year when following these guidelines. They are cold-beneficial plants; providing a cold treatment reduces the time to produce blooming plants and enhances the uniformity of bloom. It is beneficial to bulk achillea under naturally short days for 4-6 weeks prior to providing the cold treatment. I recommend providing cold to plugs or small containers for 10 weeks at 35-40¡ F.

After the cooling is achieved, provide photoperiods (day length) of 16 hours by extending the day if necessary or using a 4-hour night interruption during the middle of the night, providing a minimum of 10 foot-candles of light at plant level. Tutti Frutti cultivars are facultative long-day plants. Although they will flower under any photoperiod, they will flower best (more rapid, uniform and consistent) under long day conditions.

The time to bloom after the proper photoperiod is provided is a function of temperature. At 68¡ F, it will take 9-10 weeks to reach flowering when using vernalized materials, while plants grown at 65¡ F will flower in 11-12 weeks. Growers using unvernalized starting materials can expect to add an additional 1-2 weeks to the above finishing times.

Availability

Achillea millefolium Tutti Frutti is brought to the market by Blooms of Bressingham. Unrooted cuttings and rooted liners can be acquired from Yoder Brothers, Inc. (www.yoder.com).