Rotate Pansies on a 4-Year Cycle

yellow 'Giant' pansies

yellow ‘Giant’ pansies

Could you help me determine my problem with growing pansies? They seem to grow briefly after being planted, then wilt; I can pick up the entire wilted plant because the roots are nonexistent. One year the nursery said I planted too late (March) in the season. This year I planted during the second half of October with the same results. They were not planted in the same location, but growing conditions are similar – morning sun, shade by 10 a.m. to noon.
– Vera Sweeney, Van Nuys
Your wilted pansies – this year and last – have the classic symptoms of fungal wilt. This is a disease brought on by compacted soil, leading to excess water in the root zone. In warm winter climates like ours, pansies do best in full sun, although they will accept moderate shade. Even if your pansies did grow, they would probably be spindly, since they are already in the shade by 10 a.m.
You were correct to plant in October. Pansies planted in October have been known to flower until June. You were also wise to move this year’s pansies to a different location from last year’s; the fungi that kill pansies may persist in the soil from one year to the next.
The best way to prevent soil fungi from attacking your pansies is to prepare the soil with lots of organic material (12-15 cubic feet of compost per 100 square feet of planting area). In this preparation process, you will invariably create a raised bed, giving your flower roots lots of oxygen and the good drainage that keeps soil fungi at bay. Still, because of the buildup of pathogenic fungi even when growing conditions are perfect, it is a good idea to rotate annual flowers in a three- or four-year cycle; one winter you plant pansies, the next winter snapdragons, and the following winter dianthus, to be followed the fourth year by pansies again.
Soil fungi are a painfully familiar subject to flower gardeners. Ann Gabrik, a plant pathologist from the Soil and Plant Laboratory in Orange, has a suspicion that the same fungi that kill pansies may also be responsible for the untimely death of petunias and annual vinca. She believes it is a mistake to replace winter pansies that have died from a fungal wilt with spring petunias; likewise, petunias that suddenly deteriorate have probably been victimized by a fungus, and should not be replaced with summer vinca (Catharanthus rosea), another fungus-sensitive annual.
The fungus that victimizes all of these flowers is phytophthora. In pansies, phytophthora attacks the roots and the crown (where stems touch the soil), in petunias it attacks the roots and stems, and in vinca it primarily works on the leaves. You can remove a wilted vinca plant and find that the roots are white and healthy, even though the leaves are practically dead. Gabrik suspects that even though these annuals are not botanically related, and even though different plant parts provide entry for the fungus, the same strain of phytophthora may be responsible for the demise of pansy, petunia and vinca.
Why do my daffodils not have any flowers, but lots of green leaves, this year?
– Shirley Marks, Woodland Hills
There are at least two possible explanations. If you purchased fancy, Dutch imported daffodil bulbs, they may give flowers for one or two years, leaves for another one or two, and then disappear altogether. These daffodils were bred for cold northern climates and gradually lose their vitality in Southern California. If you cut your daffodil leaves last year before they withered, you deprived the bulb of food needed to produce this year’s flowers. As with any bulb plant, daffodil (or narcissus) leaves should turn completely brown before they are removed.
The cats next door, plus our own, are using my flower bed as a litter box. We love cats and would not want to harm them in any way. What can I do?
– Madeline Jacobs, Woodland Hills
You might try a low hedge around your planter, perhaps with mild thorns that would deter the cats without harming them. You can make a low, protective hedge from one of the dwarf natal plums (Carissa spp.), bush bougainvillea or shrub roses. You might also plant catnip (Nepeta cataria) or catmint (Nepeta faassenii) in another part of the garden to divert your cats’ attention from your flowers.

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