These perennials, bulbs, shrubs, and vines are slow to break dormancy.
This isn't necessarily a bad thing, because it's a habit that
protects the plants from damage by late frosts. However, it's a
habit that does encourage damage by humans, as gardeners begin
poking, looking for signs of life.
We know from bitter experience how heartbreaking it is to destroy an
unlabeled mature Platycodon with a careless thrust of a spade in early
spring, because it looked as though there was an empty spot in the border.
Perhaps we can help you avoid similar losses. Here are the plants we've
found to be late to greet spring.
PERENNIALS:
Unless tucked into a protected spot, perennials at the northern edge
of their hardiness zone tend to emerge later than we might otherwise
expect.
The last plants to emerge in spring include Leadwort (Ceratostigma),
Milkweed (Asclepias), False Indigo (Baptisia),
Ferns, Balloon Flower (Platycodon), and Hibiscus,
including the shrub, Rose of Sharon (Hibiscus syriacus). Ferns
sometimes don't emerge until July. Primula viallii is the last
Primula to bloom, and also usually the last to sprout, so it can be
a bit disconcerting if you have planted a variety of Primroses and one
appears to have gone missing.
Bloodroot (Sanguinaria) can be tardy the first year after
planting. Lady's Slipper Orchids (Cypripedium), Solomon's
Seal (Polygonatum) and False Solomon's Seal
(Smilacina) sometimes don't appear above ground at
all the first year after planting. However, they're establishing
an astonishing network of roots and will be all the bigger and more
beautiful the following year. That's not always much consolation
the first year, though, we admit.
If it's been a very wet winter, or if they're planted in
a spot that's too moist, Astilboides and Darmera
can also be painfully slow to awaken.
BULBS:
The first year after planting, spring-blooming bulbs often delay their
appearance. Daffodils (Narcissus) in particular often
bloom weeks later than their brethren who've been in the garden
for a couple of years. After the first season, the biological clock
recalibrates to North American time.
Lilies can also be slow the first year. It's all too easy
to behead the bulbs when all the growth is still below ground, so mark
the place where they're planted, and exercise caution during spring
cleanup. Lilium martagon sometimes fail to appear at all the
first year, as bulbs devote all their energy to establishing a root
system.
Crinodonna and Tuberose (Polianthes tuberosa), tender summer
bloomers, are often slow.
SHRUBS and VINES:
Sweet Pepperbush (Clethra alnifolia) is among the last
shrubs to leaf out. Many North American natives, such as Clethra, apparently
found some evolutionary advantage to being late to awaken. Late frosts
often spoil the display of trees such as Magnolias and Apricots, and
Clethra avoids that fate. It's not a native, but Clerodendron
(Harlequin Glory Bower) can also be slow. Talking about this subject
in the office generated some interesting differences of opinion about
Butterfly Bush (Buddleia). Some of us find it slow in
some years, and others find it prompt; which just goes to show that
location (how much protection the site affords, and which direction
it faces) has a profound impact on emergence and bloom time. At the
northern end of their range in Zones 5 or 6, Buddleia, Clerodendron,
Hydrangea arborescens ‘Annabelle' and Caryopteris
X clandonensis ‘Dark Knight' may die back to the ground—prune
off the deadwood, and the plants will break from the stubs that remain.
The first year after planting, Clematis may also be slow to
emerge in spring.
