desiGn and its relationshiP to Maintenance 25
hybrid delphiniums. These delphiniums, for instance, generally are not cold, wet,
or heat hardy; they are subject to a long list of disease and insect problems; they
need to be staked, thinned, deadheaded, and cut back for best performance; and
they require summer fertilizing to maintain vigor.
All perennials need some form of maintenance, and we would have a pretty
short list of perennials from which to choose if we insisted that they possess all
the characteristics of easy care. The typical lower-maintenance perennial will
have most (approximately four-fifths) of the following traits:
w Life span of 5 or more years
w Cold hardiness
w Heat, humidity, and moisture tolerance
w Doesn’t require frequent division
w Doesn’t require daily deadheading
w Doesn’t require staking
w Insect and disease resistance
or tolerance
w Doesn’t require numerous prunings to maintain acceptable foliage
or habit
w Doesn’t require heavy fertilizing
w Not invasiveA perennial that lives 5 or more years is considered a long-lived perennial.
Some examples of long-lived perennials include peonies and species of Baptisia
and Dictamnus. Some perennials are tolerant of extreme cold temperatures but
are killed by wet soil conditions over the winter. Likewise, many perennials
tolerate heat well but can be weakened or killed by summer humidity.
Silver-foliaged plants are particularly susceptible to high humidity and can rot.
The U.S. Department of Agriculture’s Plant Hardiness Zone Map is the most
widely accepted resource for figuring out hardiness zones, and the updated map
reflects the changes in climate regionally. Visit planthardiness.ars.usda.gov and
find your exact zone by entering your zip code.
For a lower-maintenance perennial, look for one that can last at least 4 years
before division is necessary. Some perennials don’t ever need division and may
even resent it.
Many Coreopsis lanceolata and C. grandiflora cultivars require daily deadhead-
ing to look their best. To call this high maintenance is an understatement. A
better selection would be the C. verticillata cultivars, particularly ‘Moonbeam’,
which can be sheared once for continual bloom for most of the summer.
Staking is an unpopular aspect of perennial gardening and consequently it is
often put off until the last minute, when it is usually too late. Select a lower-
growing cultivar if possible, or prune to reduce the need for staking. For example,
Gaura lindheimeri ‘Whirling Butterflies’ would be a better choice than the straight
species because it is more compact.
Perennials should be chosen that are resistant to disease and insects, or at
least tolerant to the point that either they are not bothered to any great degree or
they can be pruned to help recover from the problem rather than being sprayed.
Spraying is an area where I will not compromise. I love gardening, but I hate
spraying chemicals for pest control for many reasons. So I don’t. I would rather
do anything else as far as maintenance goes. This is another reason why proper
plant selection is critical.