This cupcutter plug is held together by Poa annua roots. Lifted from its hole with a barbecue fork, it did not break.

2001 Leo Feser award candidate

Poa annua's use on greens is here to stay. Understanding the life cycle of Poa is the key to successful Poa management. Never make a fertilizer application to a cool-season turf species like Poa just before summer stress. An alternative spikes policy and walking greensmowers should be mandatory if you have Poa greens.

I wish that long ago, when I was a newcomer to the profession, some of the old-timers would have helped me with my Poa annua greens. There was (and still is) plenty of advice for eradicating this turfgrass species, but Poa survives and even thrives to this day.

After 38 years of growing Poa greens (many years of great greens and only a couple of bad ones), it's my turn to be that knowledgeable old-timer. I might add that our ability to grow Poa greens gives us old-timers a certain level of job security. How many times have you heard that it's a fickle grass and will surely give you grief? We oldsters can grow Poa greens because we've had to. Because the youngsters in the business don't have experience with Poa greens, and today's college curriculum still doesn't teach this combination of art and science, job security comes to those who have the ability.

You've heard it before, and you'll hear it again: When Poa annua is good, it's the best; when it's bad, there's not much worse. Poa greens have been in play for decades and, like it or not, they are here to stay. Some of us want the challenge and the results. All of the major championships of golf have been played on Poa greens, and most all of the old, mainline clubs now have Poa greens. If your course does not have Poa greens today, wait a few years and you'll see.

That's OK in my book because in my experience Poa annua is a stronger species of turf than bentgrass. How many times have you tried (and failed) to seed bentgrass into a Poa green? What crowds out bentgrass during the spring and fall, and what replaces bentgrass if it dies? You know the answer is Poa annua.

We all know that Poa and bentgrass can coexist on a putting green, but they're not really compatible. Each has its own distinct management and maintenance needs, and I believe a superintendent needs to make a commitment to grow one at the expense of the other. Both grasses are at their strongest during different seasons of the year -- Poa during fall, winter and spring, and bent in the summer.

The real secret is to keep Poa alive during the stressful summer months. If you do the right things at the right time, your chances of success are greatly improved. With Poa annua greens, don't experiment and don't shoot yourself in the foot. Use your common sense and good, basic turfgrass management science. In addition, I offer my top 10 tips for dealing with Poa.

Root growth is prolific in these hydroject holes and aerifier holes filled with sand.

1. Know the Poa life cycle. Know, understand and work with the life cycle of Poa annua. You can't change it. Poa is a winter annual (seed to seed in one year), with seed production in the spring and germination in the fall. It's a prolific seed producer and, as a result, genetic variation and "survival of the fittest" have occurred over a period of many, many years.

Poa also has developed three distinct ecotypes: annual, biennial and perennial. The best Poa annua is the perennial ecotype because it's the strongest and produces the least amount of seed in the spring. If you're fortunate to have this perennial ecotype, make an all-out effort to keep it. If lost, it's replaced with the annual ecotype, which will cause a giant headache, and it will take years and years for the perennial ecotype to dominate once again.

The annual ecotype produces the most seed, which causes bumpy putting surfaces in the spring. In addition it's a real challenge to keep it alive during the stressful summer months. Annual Poa has a phenomenal seed reserve in the soil (14,000 seeds per square foot), and not all will germinate in one year. Of those that do germinate in one year, 70 percent germinates in the fall and 30 percent the following spring, which is why Poa annua eradication/control programs on putting greens are doomed.

2. Don't convert. Forget about converting Poa turf to bentgrass. It doesn't work. I've seen too many dismal failures (and too many jobs lost). The only successful conversion is through total renovation or reconstruction. Fairways are a different story, and you indeed can be successful with a conversion program.

3. Grow roots. To grow Poa annua successfully, you must grow roots, and this begins in the fall. Fall is the most important time of year as you are growing next year's greens. In the fall, Poa either begins from seed or, if it is the biennial/perennial ecotype, it's weak from the stresses of summer.

It needs to grow a root system quickly, and that begins with a fertility program. In my experience, granular products grow roots and sprayable products grow leaves. Most commercial lawn-care operators apply only sprayable products because they provide good-looking tops for homeowners interested only in good-looking lawns. My greens do receive sprayable fertilizers, but at light rates (no more than ¹/10 pound of nitrogen per 1,000 square feet) and only during summer when color needs improvement or ballmarks and cup scars are not healing quickly. I apply 99.9 percent of my fertilizer during the fall in ¹/10-pound biweekly applications beginning in late August, with a total of 2½ to 3 pounds of nitrogen. The secret is to use only granular products with 100 percent water-soluble nitrogen sources because you want immediate release of nutrients that will push the young, tender Poa annua plant to produce both root mass and root length.

Winter blankets provide really unbelievable results for Poa.

A word of caution: We all know that nitrogen drives greens speed, and if you have an important tournament in the fall, either expect slower-than-normal greens or make no fertilizer applications two to three weeks before the event. During fall aerification don't forget an application of gypsum (15 pounds per 1,000 square feet). This does wonders to flocculate the soil, which improves soil texture, which in turn increases pore spaces where roots will readily grow.

My final application of a granular product occurs just before winter blankets are installed, and it is a 1-pound rate of nitrogen from a sewage sludge material. Never apply fertilizer to any cool-season turf species (especially Poa) just before the summer stress period. If you do, photorespiration will occur, and your root system will shut down and become dysfunctional.

4. Aerify. To maximize root growth, aerification is essential. If you can aerify twice per year, aerify both times in the fall with ½-inch coring tines. Again, you're improving soil porosity by reducing bulk density, and we all know roots only grow through the pore spaces in the soil. I also like to aerify during late spring with ¼-inch mini-tines, which helps water infiltration and percolation during the summer. Late spring is Poa seeding season, and I like to aerify and topdress heavily at this time to smooth the putting surface. This seeding stage uses much of the Poa's carbohydrate reserve, often at the expense of its root system.

At a GCSAA seminar years ago, a noted researcher stated that Poa annua must grow a completely new root system after its seed production, and this complete regeneration occurs in some years but not all. I suspect the annual ecotype is the most affected, which is why it's so sensitive during the summer. That also explains why some years you have good greens and other years not so good.

I do not advise deep-tine aerification at any time. This procedure can rip and tear Poa turf (especially its root system), and the healing process takes a long time.

My topdressing program uses straight sand only, which is applied in sufficient quantity to fill most of the holes after aerification and then light applications on a three-week interval throughout the golf season. Again, you want to reduce the bulk density of the soil and increase the pore space through which roots readily grow. Core aerification and straight sand topdressing will do this for you.

5. Use winter blankets. In the northern regions, I heartily endorse using winter blankets to lengthen the "root-growing season" well into early to midwinter. You won't believe the results, and your greens will be absolutely pristine when you uncover in the spring. Remember that Poa is a winter annual: It wants to grow during the winter, so do what you can to help it grow. I'll cover my greens around Jan. 1 and remove the blankets around March 1, so there will be only two months of temporary greens. If this is a tough sell to golfers, show the results by covering only one green (or half a green) next winter. Before covering, however, make sure you have applied a product that controls both brown patch and snow mold. I would not, however, use pentachloronitrobenzene (PCNB) because it's too hard on tender Poa turf.

6. Don't . . . In the spring, most people apply pre-emergent herbicide for crabgrass/goosegrass control. Don't do it; you're still growing roots. All of these products are root pruners and will somewhat negate root-growing efforts. A post-emergent herbicide or a pocket-knife will do just fine.

Another "don't do it" is don't apply plant growth regulators (PGR). Poa is so touchy and tender that an application of any PGR (or an overlap) could cause problems, particularly during the summer. I've seen a half-rate application result in excellent control -- as in 70 percent dead. Remember that Poa is at its weakest and most vulnerable stage of growth during the summer.

7. Hydroject. Hydroject, hydroject and hydroject. The more holes you poke in the soil, the more avenues you provide for root growth. My schedule is to hydroject weekly from May through September. That's a lot of hours dedicated to this procedure, but it's that important. I hydroject four greens per day (ahead of the mowers), or if Monday is a non-golf day, my machine will not stop until all holes are finished. Hydrojecting is a cumulative process and not just a one-time deal. In a 4¼-inch cupcutter plug, I've counted as many as 76 hydroject holes, each one full of roots and air.

Hydrojecting also improves the infiltration and percolation of water, thereby keeping the surface of the green as dry as possible. This leads to the use of wetting agents. If you use wetting agents, select one that does not keep the surface of the green too wet.

I mentioned that a deep-tine machine should not be used on a Poa green, and here's why. During the summer, all root systems (including Poa's) will normally and naturally become shallow. If you deep tine in the fall, Poa roots are not deep enough to hold the turf down, and it may rip, tear and even roll up like a carpet. If you deep tine in spring, the roots will be there but the soil temperatures are low, and it will take far too long for the holes to heal. A very suitable deep-tine substitute is a hydroject machine equipped with the biggest nozzles available. I installed six of these big nozzles on my machine, and had ¼-inch holes up to 12 inches deep.

8. Manage water applications. Water management is critical to avoid turf that is too wet or too dry. With Poa, you'll spend many afternoons with a hose in your hand, and you'll become very proficient at syringing greens, with some days requiring cooling every other hour. It's not unusual to eliminate irrigation with your system during the summer in favor of hose watering.

9. Control diseases. Be sure to have a preventive plant protectant chemical program in place for the control of summer patch and anthracnose diseases. They can be devastating to Poa annua greens.

10. Go spikeless. Most courses now have a spikeless shoe policy, which is absolutely mandatory if you have Poa greens, as is the use of walking greensmowers. Equip the mowers with solid front rollers, and mow the cleanup loop only every other day during stressful times. I've found that Poa favors a tight cut (at or about ¹/10 inch). If you mow that low, have your best staff member on the cupcutter and you'll avoid the "scalped plug syndrome."

You can have good-looking and great-putting Poa annua greens. They're not easy to grow, and you'll work hard, but that's life on any golf course. It also helps if you go to church -- you'll appreciate the divine assistance.

Merrill J. Frank is CGCS at Columbia Country Club in Chevy Chase, Md., and a 31-year GCSAA member. He presented this information at the Innovative Superintendent Sessions at the conference and show in New Orleans.