Lobelia cardinalis
cardinal flower
c ampanulaceae
Bright red flower spikes; narrow foliage
3–4 ft. high; 2 ft. wide
Part shade
Blooms July–September
Zones 3–9
pruning Deadheading can improve
the overall appearance of the plant and
may result in some sporadic rebloom.
Do allow at least some of the flowering
spikes to produce, and then drop, seed
before deadheading to ensure
seedlings of this short-lived perennial.
Plants can also be pinched or cut back
before flowering to produce more
compact plants. Flowers of pruned
plants usually will be more numerous
but smaller and slightly delayed,
depending on when the plants are
pruned.
other maintenance Getting the
plants through the winter is the trick.
Leaving the stems on the plant for the
winter, as in nature, may be beneficial
for overwintering. Although native to
wet sites, cardinal flower in a garden
setting seems to do best in moist,
high-organic soil that doesn’t stayoverly wet in the winter. It also
benefits from a light mulch for the
winter, but be careful because too
much mulch can kill the plants;
remove mulch as soon as the soil
warms in the spring to prevent losses.
Self-sown seedlings are the surest bet
for longevity in the garden. Division
can be accomplished by separating a
side rosette from the parent plant in
the early autumn. Dividing and
moving the clump every 2–3 years can
increase vigor.
related plantS Lobelia
cardinalis ‘Golden Torch’ offers
brilliant red flowers against glowing
yellow to lime green foliage. ‘Queen
Victoria’ has red flowers and bronze to
red-purple foliage. ‘Queen Victoria’
cut back by half in mid-June when 2 ft.
tall flowered at approximately 2 1/2 ft. in
mid-August. Plants normally reach
4–5 ft. tall. The smaller flowers
produced with pruning are nice for
smaller cut flower arrangements.
‘Black Truffle’ is one of the newest of
several vegetatively propagated,
purple-foliaged cardinal flowers that
is hoped to be an improvement on
‘Queen Victoria’, whose foliage color
has been diluted over the years, due to
seed-propagated plants with weaker
color making their way into the
marketplace.
Lobelia siphilitica, great blue lobelia
(zones 4–9), can be pruned as for L.
cardinalis, although some prefer to just
pinch plants in early July. I’ve also
heard of good results cutting plants
back by half when 4 in. tall and again
when 16 in. tall.
Lobelia ×speciosa (zones 6–9) is a
group of hybrid lobelias that includes
blue, red, and purple bloomers.
‘Compliment Deep Red’ features
wine-red flowers on 3-ft. plants, and
‘Dark Crusader’ has red flowers and
reddish purple foliage. ‘Monet
Moment’ has blooms of pink, while
‘Fan Blue’, ‘Fan Burgundy’, ‘Fan Salmon’,
and ‘Fan Scarlet’ cover the whole
lobelia spectrum. Unfortunately, many
of the hybrid lobelias have proved to be
short-lived like the species.Lobelia cardinalis