Weeds: Friend or Foe   Weed n. any undesired, uncultivated plant, especially one growing if profusion so as to crowd out a desired crop, disfigure a lawn, etc.   How many times have we walked onto a project and saw those pesky weeds. Sometimes they look healthier than the plants we are trying to grow. Weed control is not rocket science, less than 5% of our labor budget is spent on weeding.   Know your enemy, weeds are classified by: Leaf Structure- Dicot (broad leaf) and Monocot (blade leaf) Life Cycle- Annual (they will complete their life cycle and die in one year) and Perennial (the plant continue to exist year after year) Where they are growing- in the turf or in flower beds.   Is it a weed? When I was taking my plant ID courses at Cal Poly the final exam for herbaceous plants started at a local community park. The class had gathered and the instructor gave us a brief overview of what to expect on the exam. He then informed us that the first plant to ID was at our feet in the turf. the plant was Bellis perenis, English Daisy, I will never forget that, because it was the only plant I got wrong that day. I later found out that the parks department planted English daisy in the turf to give it a more natural meadow like appearance. The moral to that story is 'one persons weeds is another persons English Daisy.' Before you start treating flower beds and turf for weeds make sure it is considered a weed.   What is acceptable? As a contractor I meet with the client and decide what population of weeds is considered acceptable. Some clients don't want weeds in the planter beds but will be more tolerant with weeds in turf and vice a versa. The eradication of weeds is always based on a percentage of control. The most expensive percentage is the last 15%. A project that is 85% weed free, in most cases, is more than acceptable. By determining what is acceptable might save a great deal of time and money for both parties.   What program is best suited for your situation? Three basic ways to control weeds are: Mechanically- Removing them by hand pulling or hoeing, the least amount of residual control which will cost more over the long term as well as causing the most damage to desirable plant material. Chemically - Applying post-emergent or pre-emergent herbicides, a better residual control but can also be damaging to desirable plant material if not applied properly.   Cultural Practices - Performing all the tasks that are normally included in a comprehensive full service maintenance program, mowing at proper heights, fertilizing with the right materials at the right time, top dressing the flowerbeds, etc. We have found that the best weed program is a strong cultural program with a properly timed chemical program and as little mechanical removal as possible.  If your gardeners don't' do the cultural things necessary to maintain the landscape properly, no matter how effective the other controls are you will always be fighting weeds, which means that your landscape is slowly deteriorating. A good weed eradication starts with good cultural practices to improve the health of the landscape. Make sure the landscape is not over or under fertilized. Mow the turf at the proper heights (which will change depending on the season) Aerify and verticut the turf as needed. Mostly importantly do not over or under water the landscape. Weeds in turf. (1) Timing is critical for proper weed control in turf.  Pre-emergents should be applied just prior to seed germination and post-emergent chemicals need to be applied during the growing season of the target weed.  (2) Then continue the good cultural practices, this will insure the best possible success for a weed free turf. Weeds in planter beds are best controlled as follows.  (1) Chemically treat all existing weeds with a post-emergent.  (2) mechanically remove the dead weeds and any weeds missed by the chemicals.  (3) Apply a pre-emergent herbicide (the ground can be cultivated prior to the application or pre-emergent which will increase the effectiveness).  (4) Install a 1" layer of mulch over any bare soil (this treatment should be done twice a year with one additional application of pre-emergent during the year) (5)  Then follow good cultural practices to insure against a future weed infestation. Weed control does not have to be difficult.  Follow a few simple rules, ask the right questions and make the environment hostile for them.  Weeds in your garden should be the least of your worries.