The Well-Tended Perennial Garden The Essential Guide to Planting and Pruning Techniques, Third Edition

Eryngium planum ‘Blaukappe’ (blue

cap) and ‘Blue Glitter’. ‘Blue Hobbit’ is

a dwarf selection reaching only 8–12

in., while ‘Jade Frost’ offers

cream-variegated foliage to go along

with the blue blooms.

Eryngium amethystinum, amethyst

sea holly, has large steely blue flowers.

‘Sapphire Blue’ is sterile and will not

produce unwanted seedlings.

Eryngium yuccifolium, rattlesnake

master, is a native North American

prairie plant with rounded, spiky

white flowers on stalks stretching to

4–5 ft. It may need staking in rich or

well-irrigated soils.

Euphorbia epithymoides

cushion spurge

euphorbiaceae

Yellow flowers in clustered inflorescences;

green leaves

12–18 in. high; 18 in. wide

Full sun

Blooms April–May

Zones 4–8

pruning Plants can be sheared back

by a third and shaped after flowering

but before seeds mature. Plants are

heavy seeders, and shearing not only

quickly takes care of deadheading but

also helps produce a nicely shaped

plant that is less likely to open up in

the center. Hedge shears work well for

this task. Euphorbia species produce a

sticky milky sap that can cause severe

skin irritation in sensitive individuals.

It is best to wear latex gloves when

pruning these plants.

Plants can be left for the winter and

cut back in the early spring. In south-

ern areas plants may act almost like a

subshrub, with buds breaking from old

stems to create 3-ft.-wide plants. Plants

allowed to develop this way in other

parts of the country generally will not

be as compact or as well formed, and

pruning down to the base in the spring

is likely to be more desirable.

other maintenance Requires

well-draining soil, tolerates drought.

May be susceptible to wilt in heat and

humidity. Can be invasive in overly rich

soil. Resents transplanting, and often

doesn’t require it for 10 years or more.

If desired, divide thick fleshy roots,

carefully, in the spring. Benefits from

afternoon shade in southern gardens.

related plantS Euphorbia griffthii,

Griffith’s spurge, can be pruned after

flowering as described above for E.

epithymoides, or it may need to be cut

back even harder (by two-thirds) to

control flopping stems.

Euphorbia myrsinites, myrtle

euphorbia, self-sows prolifically. Cut

back flowering stems before the seeds

disperse. Foliage remains an attractive

blue-green through the winter if

protected from afternoon sun and

winds. Clean up as needed in early

spring.

Eutrochium maculatum

‘Gateway’

‘Gateway’ Joe Pye weed

compoSitae

Rose-pink flower heads on tall stems;

whorled leaves (in circular clusters around

the stem)

Blooms July–September

5–6 ft. high; 3–5 ft. wide

Full sun

Zones 4–8

Euphorbia epithymoides