Plant of the week – Curl-leaf Mountain Mahogany

grey bark of young branches

I just love Curl-Leaf Mountain Mahogany (Cercocarpus ledifolius) and it is way under-utilized in landscaping!

This xeric shrub – actually more like an architecturally diverse tree when it is happy – survives drought with aplomb and thrives in rocky, poor soils as well as loamy soils.  It is just fine with extreme temperature ranges so it is great if you have a hot, dry spot but it doesn’t mind wind and cold.  Mature plants may reach 30′ in height and are very long lived.  Supposedly one was known to be 1350 years old and succumbed only to a saw.

flowers

Often found on rocky slopes throughout the Western US, it is browsed by a variety of mammals (including cottontails and deer.)  When browsed it becomes bushy and thick but it’s natural habit is upright and slender when young, creating a large multi-branched canopy when mature.

Curl-leaf Mountain Mahogany’s beautiful light grey bark is a terrific background for it’s dark green leaves, which though narrow, elliptical, curved (hence the common name) and rather leathery, are evergreen!  Clusters of yellow-orange trumpet-like flowers cover the branches in early summer.

Curl-leaf Mountain Mahogany shrub

Slender, tapered achenes (seeds) approximately 1/2″ in length have two inch long, curled, wispy awns that make the shrub look like it has curly hair.  Seed production is quite variable depending on the climactic conditions of various years.

This beautiful member of Rose (Rosaceae) family is useful as a focal point of a large garden space or in a landscape setting that calls for a plant with visual movement and interest.  It’s hardy, needs little care and provides green color all year long.

flowering branches of Curl-leaf Mountain Mahogany

Planting seeds

Fall is the best time to put established plants (ie in pots) into the ground.  Hands down, no contest.

Plants will need to be watered for a few weeks to help roots make connections with the soil around them and in fall we typically get rains that help moisten the soil sufficiently to allow roots to establish in the soil before winter freezing which prepares plants for rapid growth in the spring.

Fall is also the best time for planting seed of many species of native plants.  This mimics what happens in the wild where seeds naturally fall from plants onto the ground during the heat of summer.  If not eaten by insects, birds or small mammals and if they land a site that can maintain moisture, they will germinate.  Some seeds germinate in early fall and remain green underneath the protective blanket of snow.  Others need to undergo periods of cold, moist stratification and respond to changes in light and temperature before they will sprout in the spring.

Some native species prefer spring sowing, especially asters, grasses and some dry land species.  These species typically require warm temperatures as well as moisture for germination.  Many of these species are found on the open plains.

Arrowleaf Balsamroot (Balsamhoriza sagitatta) seeds

Montana species best for springtime planting:

• Aster spp. (Aster species)
• Fleabane spp. (Erigeron species)
• Blanket Flower (Gaillardia aristata)
• Dotted Blazing Star (Liatris punctata)
• Blue Flax (Linum lewisii)
• Black-eyed Susan (Rudbeckia hirta)
• most grass species

Blanket Flower (Gaillardia aristata) seeds

 

Montana species best seeded in the fall:

• Pussytoes (Antennaria species)
• Columbine (Aquilegia species)
• Arrowleaf Balsamroot (Balsamhoriza sagittata)
• Harebell (Campanula rotundifolia)
• Sticky Geranium (Geranium viscosissimum)
• Prairie Smoke (Geum triflorum)
• Scarlet Gilia (Ipomopsis aggretata)

Whether planting in spring or fall, seeds may be sown either directly onto a site or into containers for planting out after seeds have germinated.
Each method has its advantages:

Direct sowing:

• only have to plant once
• less materials (no seed starter or pots to use)
• cheaper (in terms of resources and time)

Sowing in containers:

• easier to monitor and control moisture levels as seeds germinate
• greater success rates
• less predation (by birds and animals)

Whichever method you use, the critical time for all seeds is when they begin to germinate. Seeds must be kept moist until they establish their roots into the soil, usually this takes about 2-3 weeks.  If they dry out even once they will die.

If you are looking for seeds of native species:

• collect your own and store them in paper envelopes
• buy from reputable companies like Native Ideals Seed Farm in Arlee, MT that specialize in native species
• share seeds with friends that you know gather seeds in an ethical manner

A Plant in a Pot is Not the Same as a Plant in the Ground!

Plants in pots are not as winter hardy as plants in the ground – we all know that – and most of us have lost our share of plants we had hoped would make it through the winter in a pot.

Thimbleberry in a pot

Often the issue is not winter freezing, but the thaw-freeze cycle of spring.  Native plants expect to freeze, but they also expect to have their roots nestled in soil that maintains warmer and more consistent temperatures than above ground.  Plants in pots are exposed to the dramatic changes in temperature often suffering root damage as they warm in springtime sunshine followed by freezing at night.

so… how to get potted plants to survive:

Avoid dark-colored pots that heat up quickly in the sun.  Unfortunately for those of us in the nursery business who use black plastic pots (used to keep roots dark during the growing season), avoiding using dark pots is not realistic.

A second option is to nestle pots in an insulating material that prevents sunlight from hitting the pot and keeps temperatures more consistent.  This may be accomplished with compost, straw, pine needles or whatever mulch material you use.

Third, consider moving pots to a shaded spot where sunshine won’t hit the pot in spring.  This helps moderate temperature fluctuations.

Stonecrop in pots

Other tips:

• Make sure pots have adequate drainage to minimize how much time the plants roots are sitting in water as the pot thaws in the spring.  Roots drown if sitting in water for more than a week or so.
• Avoid overwintering in unglazed clay pots that crack as water in them freezes and thaws.

Most native species winter nicely in protected pots.  We’re experimenting with planters and have been pleased with the overwintering results.  Tell us about your experience with overwintering in pots!

It’s time to prune!

Rubber Rabbitbrush needs pruning!

This week we’re pruning the shrubs in our demonstration gardens as the snow melts off but before leaves emerge (yes, we still have snow!).

Pruning

Wax Currant beginning to bud

Pruning maintains the health and vigor of plants by removing dead, diseased or injured material and allows  control of the shape of the plant while promoting fruit and flower yield by concentrating the plant’s energy.

This Rubber Rabbitbrush (Ericameria nauseosus) needs a heavy annual pruning to keep it bushy and under control.   It seems like the more I chop it back, the more vigorous it gets!  Other species like this Wax Currant (Ribes cereum) and our Blue Rock Clematis (Clematis occidentalis) need more careful pruning.

Leaf buds on Blue Rock Clematis

We use very sharp, clean pruning shears on smaller plants and pruning saws on large trees.   Our pruners have been sharpened and bleached in a 10% bleach solution.  It’s important to maintain sanitation and avoid transporting bacteria or viruses on shears.

We prune using the concept of ‘apical dominance’ which means that the plant has a propensity to have one main leader with all the other branches lower than the ‘main’ branch.  Cuts are made just above buds that are pointed in the direction we want the branch to take.  Our goal is to keep plants appropriately shaped (each species has its own form) and to help keep shrubs in the demonstration beds compact.

When to prune:

• Trees and shrubs – ideally after buds swell and before leaves emerge so sap will seal cuts (fall pruning may open the
  

  emerging leaves of Columbine

  plant to disease since no sap is running to seal cuts) but light pruning may be done any time of year

• Grasses may be pruned either after flowering to prevent reseeding or in the fall if you don’t want them for winter interest in your garden.  If you wait until spring (like we have done), prune back as far as you can without damaging new growth.
• Wildflowers may be deadheaded after flowering to promote second blooms or to minimize reseeding, but leave at least half of the plant mass so the plant can accumulate sugar reserves it needs to make it through the winter.  Some flowers like this Blue Columbine (Aquilegia coerulea) need to have old growth removed to make way for regrowth in the spring.

This Mockorange needs to be thinned!

This Mockorange (Philadelpus lewisii) shrub  needs to be thinned out to promote fewer healthy branches rather than lots of spindly suckers.

And of course, pruning provides cuttings for vegetative propagation which is a subject for another blog another day.

Pruning Blue Elderberry