May is generally a period of settled weather, warm sunny days and cool nights. Early frost is common in many areas. It’s nevertheless, still a very important planting time for both flowers and vegetables. Most herbs grow far more prolifically in the cooler weather conditions. The garden is a beautiful place to spend time during what should be “the busy month of May”.


  • It’s an ideal time for planting out seedlings of petunias, alyssum, Iceland poppies, primroses, fairy primroses, bellis perennis, lobelia and a whole host of other flowers. Remember that the all-important pansies and violas perform best when planted out now.
  • Plant-up pots and window boxes with new plant material for a colourful winter and spring display. It’s best to use new potting soil.
  • May is the best month for planting up mixed hanging baskets with a selection of annuals and perennials.
  • Cutting grown basket petunias and their smaller relatives called calibrachoas are in season now. They grow best in the dry months.
  • Feed flowering annuals and perennials with water soluble fertiliser during the autumn and winter season. A 3:1:6 formula is the best.
  • Continue to disbud young seedlings to prevent them flowering too small.
  • Dead head flowering plants.
  • Stake climbing sweet peas.


  • Another important planting month for cool season crops, both seedlings and seeds.
  • Beetroot and swiss chard (spinach) are important crops for this period.
  • Lettuce, especially the crisp types grow best now.
  • Plant out young plants of globe artichokes.
  • Protect cold sensitive crops from early frosts.
  • Plant leeks for winter and spring harvesting.
  • Sow more green peas and broad beans.
  • Consider planting edible flowers (dianthus, violas, pansies, borage) amongst your veggies.
  • Harvest early crops of cabbage, cauliflower and broccoli.


  • The herb garden continues to grow prolifically. Replace any plants that are old or unproductive.
  • Sow rocket (arugula) and wild rocket seeds every 3 to 4 weeks during the cooler months for a regular supply of fresh leaves.
  • For something a little different plant-up a mixed herb hanging basket.
  • Potted herbs like basil can be moved under cover to protect them from frost damage.


  • Continue to harvest citrus and avocado crops.
  • Pick up all fallen fruit from under the trees and bury to prevent the spread of insect pests.
  • Mulch all fruit trees as far out as the drip line extends.
  • Check citrus trees for any dead or spindly wood and remove.


  • Plant out daffodil, narcissus and tulip bulbs.
  • Lilium bulbs are on offer now for planting in May and June.
  • Feed bulbs that may be starting to grow with bulb food.
  • Start planting out new season flowering sub-shrubs and perennials like marguerite daisies, kingfisher daisies, nemesias, calibrachoas, verbenas, petunias and gazanias.
  • Check for aphids, especially on conifers and the new growth shoots of many garden plants.
  • Keep azaleas and camellias well-watered and mulched with pine bark as the garden begins to get drier.
  • Plectranthus and leonotis will be coming to the end of their flowering season. Prune back after blooming.
  • Indoor house plants always make a welcome display during the cooler months.
  • In colder climates indoor gardening is a great way to keep active during the winter months.
  • Filler plants in season now – brachyscome, lobularia, lysimachia, gypsophila, felicia.


  • As growth slows the work load reduces.
  • Continue dead heading from the autumn flower flush.
  • Stop fertilising and spraying in colder areas but continue in warmer sub-tropical climates.
  • Reduce watering.


  • Last cutting or mowing month in many regions.
  • Keep the edges neatly trimmed, even if the growth has slowed significantly.
  • Keep raking up leaves.
  • Sow winter evergreen grass seeds like All Seasons Evergreen or Shade Over.
  • Water evergreen grass type lawns through autumn and winter.


  • In colder climates, get ready for early frosts. Lay in stocks of frost cover to protect cold sensitive plants from frost damage.
  • Move cold sensitive potted plants under cover.
  • Continue raking the last of the autumn leaves and putting them in the compost heap.
  • It’s a great opportunity to get on top of weed problems.
  • This is an ideal time to plant up pots and containers both new and old. Rejuvenate older pots by turning them out and planting up with fresh new plants. Potted plants need to be refreshed regularly.

Autumn paints in colours that summer has never seen.

DISCLAIMER:  The information presented on this website is intended solely as a general guide. We neither endorse specific plant varieties over others nor claim expertise in stock performance. All information is believed to be accurate, based on private inquiries and experiences, and is provided in good faith. Blackwood’s, including its employees, disclaims any responsibility for harm, loss, cost, or damage arising from the use or reliance upon any information on this website, especially if any part of the information proves to be inaccurate or incomplete. Please note that the displayed photos are not representative of current stock but are used for illustrative purposes only.