Woodsorrel, the shamrock-like plant in the foreground pictured in December, is a perennial herb that is not native to California. Some people like its yellow flowers in the spring, but it can be invasive. (Photos: Jeannette Warnert)

Tasks

• Control cool-season weeds before they mature and go to seed.
• Plants planted last spring and fall may need water if rainfall has been inadequate.
• Run sprinklers periodically through their cycles to maintain clean lines and to exercise the valves.

Pruning

• When harvesting blooms for arrangements, make cuts with an eye toward shaping the plant.
• Prune and shape dormant deciduous plants – shrubs and perennials.
• Cut away 50% of last year's growth on peaches and nectarines.
• Remove leaves from roses in January to force the plant into dormancy. This is not necessary with shrub or groundcover roses.

Fertilizing

• Apply nitrogen fertilizer to citrus trees prior to bloom.
• Always read labels carefully before applying fertilizer. Use only if necessary.

To control a nutsedge infestation, pull out the plants by hand, ensuring that the tubers on the roots are removed.

• Bare root planting season continues.
• Peas (both edible and decorative varieties) can be planted this month.  Before planting, soak dried peas between damp paper towels in a shallow dish. Cover loosely with plastic and keep towels moist.  Plant seeds when they're just beginning to sprout.

Enjoy now

• Annuals and perennials: Primrose (Primula polyantha), English primrose (Primula vulgaris), pansy (Viola), sweet violet (Viola odorata), Poinsettia (Euphorbia pulcherrima).
• Bulbs, corms, tubers: squill (Scilla bifolia), ‘Paper White' narcissus (Tazetta daffodils).
• Trees, shrubs, vines: Anthony Waterer spirea (Spiraea japonica), bridal wreath spirea (Spiraea prunifolia).
• Fruits and vegetables: lemons, navel orange, parsley.

Things to ponder

• Frost is possible when it is clear enough to see the stars.  Remember to leave frost-damaged foliage until danger of frost has passed. Prune later if needed.
• Remove fallen camellia blooms promptly to prevent petal blight on next year's flowers.