Weeds

Weeds

1. Sources

   • OM
     • seeds
     • Vegetative parts
   • Animals
     • Feet
     • Droppings
   • Wind
   • water
   • brought in plants
   • neighbouring gardens
   • dormant in the soil

2. Lifecylces

   • Annual
     • eg Stellaria media, Chenopodium alba
   • Ephemeral
     • eg senicio vulgaris, Cardamine hirsuta
   • Perennial
     • eg Convuluus arvensis, Urtica diocia survive vegetatively

3. Problems

   • competition
     • Light
     • Water
     • Space
     • Nutrients
     • Choke/suffocate
   • Cost
     • Time
     • Chemicals
     • Stress
   • H& S
     • Poisonous/irritants
       • eg nettles, deadly night shade, euphorbias
     • Structural Damage
       • eg Ivy on walls/fences,roots in drains
     • Trip hazards
   • Alternative P&D host
     • eg Senicio vulgaris groundsel host rust - hollyhocks Urtica dioica - cabbage white butterfly Stellaria media -white fly

4. Specific Situations

   • Recently culivated ground
     • Brings seeds to surface. Germinate as soon as cond fav. Anuals compete with wanted seedlings. Cultural control use stale seedbedPerenials increse if choped not removed. contact herbicide eg diquat eg Stellaria media, chenopodium alba
   • Herbaceous Perenial Borders
     • UnsightlyCompetition - light and waterCultural control dif - acess dif , may need to dig up plants to untangle peren weed roots, blanket spray dif, poss spot treat. Can hoe annuals if bare ground between plants. Translocated herbicide - systemic eg Senicio vulgaris, Urtica diocia
   • Woody Perenial Plantings
     • Ivy or convulvulus arvensis can kill or break tress and shrubsUnsightlyDiff to access roots and foliage for digging out and spraying. Annuals can be hoed out in spring. Residual herbicide
   • Lawns
     • Mowing controlls annual weedsWnwated grass sp unsightly, can impare use eg of pitches.Weeds can supress grass growthP & A weeds spread by adding cuttings to compost Use seelctive herbicide for BLW runs off grass leaves
   • Paths & Drives
     • UnsightlySlippy & trip hazardsCan damage both foundations and surfacePos probs from chemical treatment run off Diff to get perenial roots out. Can use sharpe edged implements to scrape our of cracks.

5. control

   • Non Chemical
     • Barrrier/membrane
       • Fabric
       • OM mulch
       • Non OM mulch
       • Edging strips
       • Vertical root barriers
     • Removal
       • Hoeing
       • digging
       • Stale seedbed
       • Burn-Flame Gun
     • Dense planting
     • Prevent seeding
     • Animal Grazing
     • Sp giving off suppressing chemicals
   • Chemical
     • Mode of action
       • Residual
         • eg Propyzmide - commerical use only forms layer in soil prevents germination of weeds in established woody ornamental borders. do not disturb soil after applicatioin Affects fibrous rooted mature plants
       • Contact
         • eg DiquatUnwanted veg Annual weed control rapid action on all green parts No action on roots so perennials survive
       • Selective
         • eg Mecoprop & 2-4D Broad leaved in amenity turg Established 6 mths only aviod composting clippings as per manuf Irrigate if no rain after use
       • systemic
         • eg GlyphosateOn actively growing weeds kills all. If slow growing =slow acting no rain 4-6 hrs for adsorbtionNon residual
     • Limitations
       • Safe storage
       • use for correct purpose
       • environmental
       • H&S when using
       • Legislation