Perennials for zone 5

What grows in USDA zone 5, where winters reach −10 to 0 °F, and when it flowers there.

USDA zone 5 is where the coldest night of an average winter falls between −10 and 0 °F (−23 to −18 °C). Zones measure only that one night, so they say what will survive a winter, not how hot the summer is or how long the season runs.

1227 of the planner's 1400 plants are hardy in zone 5. Below are the dozen to start with, when things flower in zone 5 month by month, the plants at the very edge of their range here, and a bed the planner designed for a zone-5 garden in full sun.

1227 plants: 721 perennials, 46 ferns, 93 bulbs, 77 grasses and 290 shrubs.

The dozen to start with

Black-eyed Susan

24 in · mid July to mid September · host plant

Masses of golden, dark-centred flowers from midsummer into fall.
Lady fern

2½ ft · grown for its leaves

The classic lacy fern: light green, finely cut, arching fronds that keep unfurling all summer.
Autumn fern

22 in · grown for its leaves

New fronds unfurl coppery red in spring and mature to glossy, dark green.
Hyacinth

10 in · mid April to early May

Dense, waxy spikes of intensely fragrant flowers in blue, purple, pink, white or soft yellow, in mid-spring.
Lady's mantle

18 in · late May to early July

Scalloped, velvety leaves that hold beads of rain like mercury, under a froth of tiny chartreuse flowers in early summer.
Japanese forest grass

18 in · grown for its leaves

The plain green species: a cascading mound of bright green, bamboo-like leaves that all flow in one direction, like water over a stone.
Mountain laurel

8 ft · late May to late June

A native evergreen with crimped, sugar-icing buds that open into cup-shaped flowers of white, pink or red in late spring, in clusters that cover the plant.
Bleeding heart

2½ ft · early May to early June

An old-fashioned favourite with arching stems of heart-shaped flowers in late spring.
Winterberry

8 ft · grown for its leaves · host plant

A native holly that drops its leaves in autumn to show branches packed with bright red berries, which last into winter until the birds take them.
Peony

3 ft · late May to late June

Large, often fragrant blooms in late spring on a long-lived plant that can thrive for decades.
Rose of Sharon

10 ft · mid July to mid September

An upright shrub with hollyhock-like flowers in pink, purple, white or violet-blue from midsummer to autumn, when few shrubs flower.
Christmas fern

20 in · grown for its leaves

The most useful native fern: leathery, dark green fronds that stay green through winter, in a tidy clump that never spreads.

When things flower in zone 5

How many of these plants are in flower in each month in zone 5, and some of the familiar ones that open that month. Spring flowers here are about no weeks than in zone 5 (the plant files' own reference zone).

Month	In flower	Opening this month
January	4
February	14
March	48	Crocus, Daffodil 'Tete-a-Tete' and Forsythia
April	150	Creeping phlox, Creeping phlox 'Emerald Blue' and Daffodil
May	408	Allium 'Globemaster', Azalea 'Hino-Crimson' and Bearded iris
June	514	Asiatic lily, Astilbe and Bee balm 'Jacob Cline'
July	492	Bee balm, Black-eyed Susan and Black-eyed Susan 'American Gold Rush'
August	435	Hosta 'Guacamole', Japanese anemone and Lilyturf
September	283	Garden chrysanthemum
October	115
November	7
December	2

A zone-5 bed

The planner designed this 16 × 8 ft (4.9 × 2.4 m) bed for zone 5 and full sun when this page was made.

A 16 × 8 ft (4.9 × 2.4 m) bed at eye level in late July: Sea thrift, Winter heath, Brown-eyed Susan, Boxwood 'Green Mountain', Wild quinine, Switchgrass 'Cheyenne Sky', Spike speedwell, Darwin hybrid tulip, Grape hyacinth, Greigii tulip. — A 16 × 8 ft (4.9 × 2.4 m) English border in zone 5, full sun, seen from the path in late July.

From above, to scale. Each circle is one plant, as wide as the room it needs.

The plants

1 Sea thrift × 14, pink
2 Winter heath × 13, white
3 Brown-eyed Susan × 8, yellow
4 Boxwood 'Green Mountain' × 1, dark green leaves
5 Wild quinine × 5, white
6 Switchgrass 'Cheyenne Sky' × 3, purple
7 Spike speedwell × 8, blue
8 Darwin hybrid tulip × 7, red
9 Grape hyacinth × 12, blue
10 Greigii tulip × 12, orange

Planned as an English border: 10 of the 12 groups (83%) are drifts, longer along the bed than they are deep. The most in flower at one time is 4 kinds, from late July. The bed is tied together by its repeats: four kinds come round again along it, among them sea thrift and winter heath.

The planner's own design check: 14 Excellent, 3 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.

Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.

At the edge of their range in zone 5

Hardy to zone 5 and no colder (302). They survive a normal zone-5 winter but not a harder one: give them the warmest, best-drained spot you have, and a mulch in their first winter.

And 272 more.