Keeping your Perennial garden in peak form
Watering
Keep a close eye on newly planted perennials the first growing year. Most
plants die because they get too much or too little water. The soil should be moist
but not soaking wet the first two weeks after planting. For the next couple of weeks;
water when soil 2 inches below the surface is dry to the touch. After that, check
the soil once a week and water if it is dry 3 or 4 inches deep.
Water slowly and deeply rather than frequently and shallowly to encourage deep,
durable root systems. A good rule of thumb is many perennials grow well with 1 inch
of water per week from natural rainfall or from irrigation. One of the best ways
to water perennials in dry summer regions is with water-conserving soaker hoses.
Water drips slowly from the “leaky” hose directly onto the soil right around plant
roots for several hours. The water then moves down through the soil to plant roots
without any waste and the tops of plants stay dry reducing the chance of disease
problems that occur when plant foliage stays wet.
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Mulch Matters
Mulch is a material spread on top of the soil to control weeds, conserve moisture,
moderate soil temperature and to keep soil from compacting after prolonged rain.
Organic mulches are ideal for perennial gardens because they break down over time
and improve the soil structure. Materials such as compost, well-rotted manure and
shredded leaves are good choices for perennial beds. Pine needles are frequently
used in the Southeast because they are so plentiful. Though pine bark is commonly
sold as mulch, it is better used around shrubs and trees than in perennial beds.
Spread a 2-inch layer of mulch over weed-free ground in the spring. If you live
in an area where it is hot and humid, apply a 3- or 4- inch layer because theses
conditions cause organic material to break down quickly. Organic mulches can be
layered on the garden every spring. If you use soaker hoses, put the hoses in place
then cover them with mulch. Don’t mulch around the crown of the plant (where the
plant touches the soil) because mulch holds moisture and plants tend to rot if the
crown stays wet.
Late summer- and fall-planted perennials should get a 3- or 4-inch layer of mulch
after the ground freezes. Once the soil has frozen, you want it to stay frozen because
newly planted perennials don’t have established root systems to keep them anchored
in the ground as the soil freezes and thaws. This is especially common in spring.
If you do find a few plants that have been “heaved” out of the ground by alternating
freezing and thawing replant and mulch again as soon as you can.
If you matched the right plant to the right place and selected perennials that are
winter hardy in your area you shouldn’t have to apply winter mulch after they are
established. The exception to this is shallow rooted perennials such as iris and
coral bells planted in colder climates. Mulch these plants 3 to 4 inches deep after
the ground has frozen.
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Grooming Perennials
After they are established, most perennials don’t need a lot of maintenance but
you do need to groom and primp here and there to keep the garden looking great.
The best policy to keep things manageable is to walk through the garden once or
twice a week with a bucket and pair of pruners in hand so you can pull stray weeds
as you see them or remove flowers that have faded that week. A few other chores
such as mulching and cutting back perennials take a little more time and may require
a few hours on a Saturday morning.
While most perennials don’t need to be staked, sometimes it can’t be avoided. If
you garden in areas with heavy summer rain or gusty wind you will probably have
to stake some plants. Tall growing perennials such as Rudbeckia Henry Eihlers and
perennials with big flowers sometimes need support.
Cutting Back and Deadheading
Cutting plants back is a useful technique that can:
- keep leggy plants from getting too tall
- promote new leaf growth
- encourage plants to bloom again
Sometimes you can avoid staking taller plants such as big asters and tall sunflowers
if you cut them back by about half in early summer. This keeps plants shorter than
normal and encourages denser growth. Other plants such as spring blooming dianthus
and creeping phlox should be cut back by one-half after they bloom to keep them
from opening up in the center and or getting thin.
Deadheading is a menacing term for removing old flowers. Many plants will bloom
again if old flowers are removed before they set seed. There are two ways to make
deadhead cuts and the method depends on how the flowers grow.
Perennials that have leaves along the flower stem, such as tall phlox and bee balm,
should be cut just above the point where you see a new bud or shoot emerging. This
is usually in the axil of the set of leaves closest to the old flower. With flowers
that don’t have leaves along the stem, such as Hosta, Heuchera, Hellebore, and Pulmonaria,
make the cut at the base of the flower stem near the ground.
When it comes to daylilies it’s a good idea to remove the individual blooms after
they fade. This helps divert energy from forming seed pods and re-channels it into
producing more flower buds. Once an entire bloom spike is finished flowering, you
can then cut the flower stem off near the base of the plant.