Sunday, September 28, 2014

Bulbs for Spring Bling

Few plants give us as much joy, color and diversity as bulbs. Their popularity is well deserved, what other plants are nearly fuss-free once planted?  Plus they don’t clash with established landscapes. Quite the contrary; they enhance perennial borders, shrub plantings, even the hell-strip.  Purchase (or divide freebies from friends), dig, drop, water, and wait.  That’s bulb planting in a nutshell, but here’s a closer look.
Photo from
Bulbs, technically called geophytes, meaning they are herbaceous underground storage units for their seasonal growth cycle.  All the nutrients the flowers require are stored neat and tidy in these small plant organs.  What most gardeners collectively call bulbs also includes other categories – corms, tubers, rhizomes, and tuberous roots.  

True bulbs like lilies, tulips, daffodils, garlic and onion consist of fleshy layers of leaves (called scales) with a small base of roots at the bottom (basal plate) that anchors the plant in the soil. Corms like gladiolus, crocus, freesia, crocosmia and bananas (not grown here, but now you know they are corms) contain a solid mass of stem tissue and grow new (baby) bulbs from the main bulb (mother).  They look similar to bulbs but are usually round in shape and slightly flattened, not pointed like a true bulb.  

Tubers, the most well-known example in the culinary world – the potato, form roots and foliage from growth buds, known as eyes. Tubers are usually short, rounded and fat with no covering.  Caladiums, poppy and Greek anemone, cyclamen, gloxinias and gloriosa lilies all grow from tubers.  Rhizomes are thickened, branching underground stems that grow horizontally.  Most grow along or slightly below the surface of the soil, sending stems above the ground. This group includes cannas, calla lilies, lilies of the valley, corydalises, wood anemone and iris. Tuberous roots look like swollen tubers.  New growth buds or eyes appear at the base of the stem during the growing season.  These include daylilies, begonias, dahlias, clivia (houseplant) and foxtail lilies. 

Bulbs truly have a wonderful life. They store up all their energy during a brief period of good weather then remain mostly dormant during harsh weather conditions.  When the weather is favorable again they grow and bloom, we smile.  They are further categorized by their hardiness and time of bloom.
Bulbs, Corms, Tubers, Photo by Brian Wilder,
The hardiest of bulbs survive our mostly zone 5 winters along the Front Range and at higher elevations and include spring flowering bulbs – crocus, daffodils, tulips and iris.  
Summer bloomers include hardy lilies and ornamental onion to tender bulbs that need to be lifted and stored over the winter or will die each fall – dahlias, gladiolas and elephant ear. 
Fall bloomers are often forgotten but should be on more lists to plant in late summer – autumn crocus and colchicums. 

Winter flowering refers to bulbs forced to bloom out of season, they are planted for winter enjoyment – paper whites and amaryllis are the most common and easy to plant.  But with a little more planning and preparation tulips, daffodils and hyacinths can be your indoor centerpiece early next year if potted later this fall.  

Bulb Essentials –

  • If you want the best display of bloom and years of enjoyment think before you purchase bargain bulbs.  You get what you pay for. 
  • Look for firm, plump, healthy bulbs in the garden center. They should feel solid when you pick them up and not have any bruises, soft spots or sour odor.   Don’t worry if they have lost their papery cover or tunic, if it’s loose you’ll be better able to check bulb quality. 
  • Read bulb packaging or labels.  If they are labeled “top size” then they are the largest commercially available size, producing more or bigger flowers than smaller bulbs.  These are usually 4 ¾ inches around or 12 centimeters.  Less expensive bulbs are smaller than 4 inches or 10 centimeters.  If you want a “look over here,” gorgeous bulb display in your yard, purchase top-size bulbs. If you’re naturalizing (planting in drifts so bulbs multiply) then it’s economical to purchase smaller bulbs, they catch up in size in a season or two anyway. 
  • If purchasing mail order, inspect them upon arrival and plant right away.  Mail order companies send orders based on your planting zone and for the most part, bulb quality is good because they are stored properly prior to shipping.  If you can’t plant right away, put them in a dry spot (indoors, 40-50 degrees) with good air circulation and keep the bag open (mesh is best). 
  • The hardest part is deciding which bulbs to plant.  Select the site first and make sure the drainage is good otherwise bulbs may rot.  Sunny locations work best, but that doesn’t have to be sun all year. Planting near or under deciduous trees that haven’t leafed out and cast filtered shade are fine locations.  Careful not to plant the earliest bloomers near walk ways where you’ll be shoveling snow.  And plant where you can see and enjoy them!
  • Spring flowering bulbs grow their best with morning sun and afternoon shade. Dahlias and cannas which bloom in the summer also need sunny locations.
  • The sequence of bloom can start in late winter running right up through summer when you can plant dahlias, cannas and gladiolas.  Start out with snowdrops, aconites, then scilla, crocus, and chionodoxa (glory-of-the-snow).  Follow with daffodils, tulips and hyacinths.  Tulips and daffodils have the most range of bloom times, look for early, mid or late varieties.  Include some of the showy flowering alliums that bloom mid to late summer.  More Bulbs - Allliums 
  • Books, magazines and on-line sources can elaborate on bulb design principles.  They’ll all say that more is better.  Plant in masses or drifts through the perennial and shrub beds and rock gardens.  You can play with varying heights adding depth and interest or plant a solid color and variety or repeat the bulbs and colors throughout the landscape. The only rule is to plant what you like and reflects your style and expression.  More Bulbomania
  • Keep in mind that certain tulips only last a year or two so should be treated like annuals. Other types will perennialize and come back if they are happy in their location and not disturbed.  Read the package or paperwork near the bin and look for these repeaters - Species tulips, Kaufmannia or Greigii tulips, giant Darwin hybrid tulips, and Fosteriana, also called Emperor tulips.  More Best Bulbs for Perennializing 
    Photo from
  • Why all the names for daffodils? The whole genus is Narcissus. Daffodil is the common name, they are larger flowered.  Jonquil is a species name within the genus, usually smaller and fragrant. 
  • September and October planting gives bulbs plenty of time to establish before the ground freezes.  Some gardeners say they still get good results when planting into November, but that all depends on our weather and how it affects soil conditions.
  • Soil preparation is important for bulbs, just like all other perennials.  They want loose, amended soil (no full clay) for room to grow with good drainage. Use a phosphorus or balanced fertilizer (5-10-5) in the planting hole.  Bone meal isn’t recommended unless you have soil pH that is under 7, which a soil test will indicate. 
  • Plant depth is three to four times the height of the bulb, pointy side up. If in doubt what side is up, lay on its side.  Plant two inches deeper if you have sandy soils.
  • For large area planting remove enough soil to accommodate all the bulbs. Fertilizer and compost or amendment can be added to the entire area prior to placing the bulbs.  Scatter or place in groups.  Just don’t plant them like soldiers, all in a perfect row.
  • Label your bulb plantings or make a drawing so you don’t disturb the bulbs next spring.
  • Water the bulbs after planting and water through the fall and winter (every 3-4 weeks) if we receive little moisture.  Use a screw driver or trowel and dig down to check soil moisture.
  • Mulch the bulbs with a three inch layer of organic matter like leaves and grass after a couple of hard frosts to maintain moisture and prevent the soil from heaving which may up-root the bulbs. 
  • Bulbs can be bothered and eaten by squirrels and mice.  They like tulips, crocus, lilies and chionodoxa.  They leave daffodils and hyacinths alone.  Enclose them with ½ inch hardware cloth boxes or dip the bulbs in a liquid repellent product like Ropel® before planting.  And remove all papery skins after planting so they won’t be drawn to the area by any lingering scent of the bulbs.
Photo credit -, Felder Rushing

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