open habit, particularly in shady sites.
It benefits from pruning as described
above, although Allen Bush, a
well-known horticulturist, reports that
plants in his North Carolina garden
grew to 8–9 ft. even with cutting back
by half in mid- to late June. This
species might need a heavier hand
with the pruners, or less southern
hospitality! It requires abundant
moisture, as the common name would
indicate, and is a heavy feeder and
seeder. Deadhead spent flowers or cut
down plants before seeds have a
chance to mature. Swamp sunflower
may be invasive in certain sites. ‘First
Light’ tops out at 4 ft. and is a more
reasonable candidate for the average
border.
Helianthus ‘Lemon Queen’ (zones
4–10), a hybrid sunflower, opens its
cheery lemon-yellow daisies from
August through September. It reaches
5–7 ft. in height but shouldn’t need
staking unless overfertilized or
overwatered. It can be pinched as for H.
salicifolius to reduce its height; stop
pruning by mid-July to give it time to
flower. ‘Lemon Queen’ may seed
around a bit, but not obnoxiously, and
the offspring will resemble the parent.
Divide in spring as for willowleaf
sunflower, every few years or when-
ever flower production slows down.
The magnificent Helianthus
maximiliani, Maximilian sunflower
(zones 4–10), is suitable for only the
largest planting areas, not only
because of its great height (to 10 ft.
when left unpruned), but also because
of its ability to spread laterally and
crowd out weaker, smaller plants. It
can be trimmed as for H. salicifolius in
June to bring it down to a more
reasonable height at flowering time.
Untrimmed, it will need heavy-duty
staking (like metal fence posts) to keep
it upright, although allowing a few
stalks to tumble to the ground and
mingle with the plants at its feet can
create a lovely effect. The blooms are
3–4 in. across and smell like cocoa.
Heliopsis helianthoides
‘Summer Sun’
‘Summer Sun’ heliopsis
compoSitae
Golden-yellow, daisylike flower heads;
green leaves
3–6 ft. high; 4 ft. wide
Full sun or part shade
Blooms June–September
Zones 3–9
pruning Young plants bloom all
summer long, almost nonstop, with