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What to do in your garden in May

During the month of May you can

Stock Up

Now is the time to purchase your herbs, lavenders, and salvias.  For variety and inspiration visit  Morningsun Herb Farm in Vacaville (707-451-9406).  There you can find an extensive range of medicinal and culinary herbs. The have as many as 40 varieties of lavender, and 60 -varieties of salvias.  Well worth the trip.

If you love dogwoods like me, now is the time to buy kousa dogwoods These shrubs (which can be trained as trees) have delicate-looking flowers in late spring and stunning red fruit and foliage color in fall.  Check out  Wildwood Farm Nursery in Kenwood (888/833-4181) for a large variety of kousas: white-bloomed ‘Angel Wings’, pink-flowering ‘Satomi’, and ‘Wolf Eyes’, which has cream-edged leaves.


  • Continue sowing salad greens Plant a small batch of seeds every two weeks until daytime temperatures reach 75°, when it’s too warm for these cool-season crops. To beat advancing heat, choose fast-growing arugula and leaf lettuce, rather than slow-maturing head-forming greens such as radicchio and romaine.
  • Veggies for containers Zones 7-9, 14-17: If you don’t have space to grow vegetables in the ground, plant them in containers. Tried-and-true favorites that do well in pots include ‘Blue Lake Pole’ beans (train them on obelisks), ‘Giant Marconi’ pepper, ‘Early Girl’ and ‘Sun Gold’ tomatoes, and ‘Eight Ball’ or ‘Spacemiser’ zucchini. Seedlings are available in nurseries now. Choose a container at least 18 inches deep and wide, and use fresh potting mix. Place the pots in full sun. Fertilize and water regularly.


  • Summer annuals.   Zones 7-9, 14-17: May is the optimum planting month for annuals. In sunny beds, plant cosmos, Madagascar periwinkle (Vinca rosea),marigolds, nasturtiums, petuniassalvia, and zinnias, from either six packs or 4-inch containers. In shade, grow coleus and impatiens. Zones 1-2: Plant after danger of frost has passed.
  • Green-flowered Nicotiana langsdorffii and fragrant N. sylvestris, ‘Aztec Sun’ and ‘Goldfinger ‘Tithonia, and tall-growing varieties of cosmos and sunflower. All grow 3 to 6 feet tall.
  • Sweet-scented, white-flowered bush anemone (Carpenteria californica), a native that needs little water and care. This plant ranks among the 100 tough and reliable plants chosen as Arboretum All-Stars by the University of California, Davis Arboretum. Find other scented shrubs on the Arboretum All-Stars website (; click on “Arboretum All-Stars”).
  • Ornamental grasses.  With their flowing habit, grasses lend a sense of movement to the garden. The following species are also drought-tolerant, take full sun to part shade, and thrive in Northern California (in zones 1-2, treat them as annuals): Elymus glaucus, E. triticoides, Festuca paniculata, and Pennisetum messiacum. If you can’t find the plants locally, order from Greenlee Nursery (909-629-9045).
  • Plant a bean tipi Gather twine, a packet of pole beans, and three to eight bamboo poles each 6 to 8 feet long. Arrange the poles in a circle and tie them together at the top. When the weather has warmed, plant the beans 6 inches apart, four per pole. Try classic varieties ‘Blue Lake’ and ‘Kentucky Wonder’; red-flowered scarlet runner; or yard-long beans (Chinese long beans), which have 2-foot-long pods.


  • Aerate lawns.  Lawns that get a lot of heavy foot traffic may have compacted soil, making it difficult for water, fertilizer, and oxygen to reach the roots. If you can’t push a screwdriver up to its handle into the turf, it’s time to aerate. You can rent a power core aerator from a landscape equipment supplier (look in the yellow pages under Rental Service Stores & Yards) or hire a lawn professional such as Shamrock Landscape Co. Aeration works best on a moist lawn.
  • Do pest control for your lawn areas.  Prevention is always better than the cure. For those of us that are experiencing problems with moles, spray your lawn areas with a suitable pesticide to get rid of grubs and other critters that moles feed on.  If there is no food to feast on moles will not wreak havoc with your lawn.
  • Thin fruit   Sunset climate zones 7-–9, 14–17: Before apples, Asian pears, nectarines, and peaches reach an inch in diameter, gently twist off enough fruit to allow 4 to 6 inches between remaining fruit. (Zones 1–2: Do this in early summer.) This improves the size of the remaining fruit, reduces the risk of broken branches, and keeps trees producing well annually rather than in alternate years.
  • Control aphids. Strip aphids from plants by hand or dislodge them with a blast or two from the hose.  Also look out for slugs, snails and Japanese beetles. Treat now to avoid major problems later.  On Roses look for black spots and mildew as well.

Well that should keep you busy for a while, happy gardening

from the folks of Shamrock Landscape Co


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