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Plant Focus: Crocus

September 1, 2020 • Leave a Comment

For a gardener, there are few sights as welcome as the first crocus of the year, peeking its flowers through the freshly melted snow of late winter. Crocus is a very hardy perennial and one of the few plants that can bloom as early as February or March. By being hidden deep in the soil, crocus corms are naturally insulated from severe temperature changes, ice and wind. Flowering is initiated by just a few consecutive days of temperatures above freezing. Once the first few inches of soil can thaw, flowers emerge and will last for several weeks despite more wintry weather. Crocus flowers can protect themselves by closing up in the evening and also whenever they experience severe weather.

**‘Yellow Mammoth’ (Photo: Dutch Gardens)**

Crocus have long been popular with gardeners for several reasons. Their durable flowers are available in many colors including yellow, white, purple, blue, and pink. One plant will usually return year after year and develop offspring that can produce additional flowers in beautiful drifts. The two-inch flowers are made up of 6 oval petals that surround 3 prominent yellow to orange stamens. Crocus grow from one-inch corms rather than actual “bulbs.” Both are just compressed stems: bulbs consisting of fleshy scales and corms being more solid. Gladiolus is another example of a corm.

**‘Whitewell Purple’ (Photo: John Scheepers, Inc.)**

Crocus are native to the rocky slopes of the Mediterranean countries and southwest Asia. They adapt to cold winters, full or partial sun, and well-drained soil. Most Michigan gardeners have the first two, but well-drained soil may have to be created if clay is prevalent. Drainage can be improved by adding aged pine bark or compost to your soil. Since crocus corms are planted 3 to 4 inches deep, only about 4 inches of soil below them needs to be well-cultivated. Corms should be at least 3 inches apart. However, this is the type of bulb that looks great planted in more natural and random masses.

Most crocus have only one serious threat to their perennial existence. Hungry bunnies seem especially tempted by the leaves, flowers and corms of several species. Corms can be protected by several methods. Gravel worked into the soil above the corms will make digging them up difficult. Liquid or powder deterrents can be used to treat corms before planting. Keep in mind that freshly planted bulbs and corms are most likely to create curiosity amongst browsers. Once established, they are rarely disturbed. If all else fails, you can plant in below-grade, wire mesh cages that are impenetrable. To protect leaves and flowers, apply a granular deterrent or a spray.

**‘Ruby Giant’ (Photo: John Scheepers, Inc.)**

There are many varieties of spring-blooming crocus but most of the hardy ones fall into four species. Crocus ancyrensis is golden bunch crocus. The selection ‘Golden Bunch’ produces up to five deep orange-yellow flowers in a “bunch” per corm. Of the four species, this is one of the earliest to bloom; late February is not unusual if Mother Nature is cooperating. This is also one of the more vulnerable to attack from the bunnies.

**‘Jeanne d’Arc’ (Photo: John Scheepers, Inc.)**

Crocus chrysanthus is available in several varieties, all of which are referred to as snow crocus or golden crocus. ‘Cream Beauty’ is a strong grower that is primarily white with a white center. ‘Ladykiller’ is also white but with purple on the outside of the petals. ‘Advance’ is yellow inside but the outside is unique because the petals alternate creamy yellow and purple. Corms produce 1 to 4 flowers each in late February or early March. Like C. ancyrensis above, rabbits admire this species.

Crocus tommasinianus is a wonderful choice for several reasons. This species is the most pest-resistant crocus available. If you have lost crocus to rabbits or squirrels, this may be the choice for you. C. tommasinianus is also the most prolific grower. It will quickly naturalize to form masses of flowers. The most readily available variety is ‘Barr’s Purple.’ Its deep violet petals fade to a bright white center that is highlighted by bright orange stamens. It blooms almost as early as the above two species, usually in early March.

The most popular species is Crocus vernus or Dutch crocus. Unlike the previous species, one large flower with large gold stamens is produced from each corm. It is available in several colors ranging from white to stripes to purples. ‘Jeanne d’Arc’ is a bright white with large flowers. ‘Pickwick’ has large white flowers with dark lavender stripes inside and out. ‘Remembrance’ and ‘Flower Record’ are deep lavender and pale lavender respectively. Dutch crocus usually bloom from March to early April.

Fall is a perfect season for planting. Cooler weather means less heat stress for both plants and people. Plants are naturally becoming dormant and are far less susceptible to drying out and experiencing transplant shock. Fall is also the only season for planting spring-blooming bulbs and corms. Once the ground freezes, the opportunity is lost and you’ll regret not having these heralds of spring glowing in your early season garden. Crocus are relatively inexpensive and are available almost anywhere bulbs are sold. With minimal effort this fall, you can enhance your existing landscape and welcome spring with the bright blossoms of crocus.

**‘Blue Pearl’ (Photo: Van Bourgondien)**

Crocus CRO-kus
Plant type: Corm (commonly referred to as a “bulb”)
Plant size: 3-5 inches tall
Habit: Clump-forming
Flower colors: Purple, violet, reddish- purple, lilac, yellow, cream, white
Flower size: 2 inches wide
Bloom period: Late winter to early spring
Light: Full to partial sun
Soil: Well-drained
Uses: Plant in natural drifts in the perennial border, lawn or rock garden
Remarks: The corms develop offspring that can produce additional flowers to create a naturalized look

George Papadelis is the owner of Telly’s Greenhouse in Troy and Shelby Township, MI.

RELATED: Colchicum and Fall Crocus

ELSEWHERE: More on Crocus at Chicago Botanic Garden

State of Michigan seeks help finding disease-resistant survivor elms

August 3, 2020 • Leave a Comment

A century ago, elegant, vase-shaped American elms shaded neighborhoods with their lacy, arched canopies. Today, many of those trees are dead, skeletal husks—a legacy of the destructive Dutch elm disease. The fungal disease, spread by bark beetles, slowly wiped out most American elms after being introduced in the early 1900s.

However, the American elm’s story isn’t over. Midwest forest health experts are working to stage a comeback, and they need your help. Have you noticed any large, healthy American elms in your area or when out hiking in the forest? Those “survivor elms” might be tolerant of Dutch elm disease. If you are in Michigan’s colder climate zones (zone 5 and colder), you especially are encouraged to report these trees. Currently, there are no Upper Peninsula reports and very few northern lower Michigan reports. It’s important that these zones are represented, because it helps provide a clearer picture of where disease-resistant elms may be.

Several Midwest state natural resource agencies and the U.S. Forest Service are working together to identify such locations. They plan to collect branch samples for propagation (the process of growing new trees from a variety of sources), with the goal of developing a seed orchard suitable for future reforestation efforts in northern areas.

Eligible elms must be:

An American elm (not an imported species).
At least 24 inches in diameter.
Disease-free.
Naturally grown, not planted or treated with fungicide
Within 1 mile of Dutch elm disease (indicated by nearby dying/dead elms).

If you come across one of these trees, record its location and diameter at 4.5 feet from the ground. Submit the observation to the survivor elm website.

Ask MG: Why are my elm leaves are turning yellow and wilting?

How do I establish moss on a shady path?

July 23, 2020 • Leave a Comment

We have a shady, worn path on the north side of our house. If I installed stepping stones there, how can I get moss to grow between the stones?

Moss has a unique beauty and has become the focus of a new form of gardening. Since it generally loves acidic, compacted, deeply shaded and poorly drained sites, moss is wonderful for locations that would otherwise be a gardening nightmare.

Four types are typically used in moss gardens: fern (or sheet) moss, the most versatile and fastest-spreading groundcover; rockcap, used for walls, boulders and pond edging; haircap, which prefers partial sun and well-drained soil; and cushion, which prefers sandy soil, tolerates partial sun and is excellent for rock gardens.

In your situation, to get moss to take hold, the first thing you need to do is make sure the growing requirements are met. Think about where you would find it in a natural setting: normally in a shady, relatively cool and damp location, like the woods, shady areas next to a stream, or under a tree where it is shaded, damp and cool.

Do a soil test first. The soil needs to be poor in nutrients and slightly acidic—the pH should be between 5.0 and 6.0; lower is okay, with 6.5 the maximum but not ideal. The soil can be amended to the desired pH with liquid sulfur or aluminum sulfate, or mix in coffee grounds or peat moss. Using Roundup to clear an area of weeds will also help create favorable moss-growing conditions. Moss plants need a firm soil bed rather than loose, fluffy soil, so if the area has been cultivated recently it should be tamped down lightly. Remove any debris, plants, or leaves (moss doesn’t like compost).

Once you have taken care of the soil, you are ready to “plant.” With some patience you can grow your own moss. You will need some moss to start. See if you can find some growing in your yard (or a neighbor’s or friend’s) in conditions similar to where you will apply it. Take a good size strip of healthy moss (remove as much dirt as possible) and crumble it in a blender. Add 2 cups of buttermilk and 2 cups of water. Blend at the lowest speed until it is completely mixed and the consistency of a thin milkshake (add water if necessary). Spread this mixture on the soil. You might need to make more than one batch.

It is imperative to keep the area slightly damp at all times! Keep an eye on it and mist regularly with water, especially the first 3 weeks. It usually takes about a month to get established but it also can take up to a year. The easiest way to ensure success would be to install misters and a timer if the area is not naturally moist or damp. You can use the same mixture (but slightly thicker) to grow moss on rocks, flowerpots, etc. Use a paintbrush to apply the mix and mist regularly to keep it moist.

Having the opposite problem? Dealing with moss in your lawn

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