GardenGuy: March tasks begin the new gardening year

Image courtesy pixabay.com

By Bruce Bennett

For many of us, February and the NW Flower and Garden Festival start the new gardening season. But, weatherwise, March marks the beginning of spring in our yards. The weather can still be just a tad bit fickle. It can be mild and pleasant one day, then, cold and wet the next. 

Until the days become consistently milder, be patient, continue to read your seed and plant catalogs and use this time to organize your thoughts and sketches about what you want to accomplish in your landscape and veggie garden this spring. I do not typically write monthly to-do lists, but March is the exception. There is soooooo much that could be done, given your amount of free time and energy.

Image courtesy pixabay.com

Generally, the soil in March is too cold and wet to work in. Just walking on the soggy soil in a vegetable bed will compress it. This compaction affects drainage and rain absorption and prevents plant roots from penetrating very deeply. 

Soil compaction also reduces the amount of open pore spaces and makes it difficult for plant roots to absorb oxygen and water. 

How to know the difference? That’s easy. Put on your gloves, dig a small amount of soil and squeeze it in your hand. If the soil stays in a solid muddy ball, it’s too wet to work in. If the soil crumbles through your fingers when you squeeze it, then it’s ready to be worked.

Once the soil in ornamental garden beds is dry enough to walk on, remove any weeds that have overwintered and think they now have seasonal squatters’ rights. It’s important to tackle weeds early and stay on top of this task throughout the growing season. This time of year, I find pop weed to be my first nemesis and use my handy Weed Dragon (homeowner’s flame thrower) on my gravel paths and patios.

Unless you are really eager to get outdoors and do some gardening, don’t be too quick to cut back last year’s dead perennial foliage. If possible, hold off on this task until daytime temperatures are consistently above 50°F for at least a week. 

Many beneficial insect species such as small native bees, Hover Flies (syrphidae), and lacewings overwinter in the debris and are simply biding their time and waiting for warmer weather conditions before emerging. By waiting for the right conditions, you give these insects the chance to emerge safely and start doing their seasonal work in your yard.

Image courtesy pixabay.com

Redefine flower bed edges as needed to give them a neat appearance. If you do not have small bed walls of one sort or another, consider using a flat-edged spade or a half-moon edger to create English-style edges that define a line between lawn and planting beds. 

Using either tool, make a straight cut down four to six inches. Then, make a second 45 degree angle from the flower bed down to the bottom of the lawn cut. The cut edge can be left as-is or filled with mulch or grass clippings. Either way maintains a distinct, weed-free boundary between grassy lawns and pathways and the perennial borders. It makes the rest of your gardening year just a little bit easier.

Assess your emerging perennials to identify any that may need to be divided. Guidelines vary, depending on who you read, on how often to divide perennials but, on average, many of perennials benefit from being divided about every four years. 

As a general rule, divide spring and early summer-flowering plants in the late summer or autumn and autumn-blooming plants in the spring. And, certainly, divide hostas just as they emerge in early spring. This will minimize damage to the leaves.

Top dress flower beds with one to two inches of compost to improve the soil structure, add nutrients, and enhance the soil’s capacity for holding moisture. Now is a good time to incorporate bare root plants and dormant roses. 

Bare root sales of 20% - 40% are generally occurring in February and March. Soak the plants’ bare root in a bucket of water overnight to rehydrate the roots. Choose the appropriate well-drained location, dig the planting hole wide enough and deep enough to easily accommodate the roots and set any plant graft so that the graft union is at soil level. And, especially with roses, space them far enough apart to allow good air circulation.

Image courtesy extension.oregonstate.edu

Now that the harsh winter winds have past, prune established rose bushes now to improve their health and structure. Make sure your pruners are sharp and clean. Prune canes to an outward-pointing bud and make each cut at a 45° angle just slightly above the bud. Remove any broken, diseased or crossing canes. Cut any damaged wood back about one inch into healthy wood. 

Cut any dead canes down to the ground. If any branches rub together, choose the healthier of the two and remove the other one. If you are pruning a grafted rose, check for suckers below the graft union and remove them. 

Proper pruning facilitates better air circulation, allows more sun into the middle of the plant, and results in a healthier, more attractive plant. Stop by the Woodland Park Rose Garden for examples of this work and, perhaps, talk to one of the Horticultural staff working in the area.

Again, depending on who you read, when to fertilize spring-flowering bulbs will vary, but, as a general rule-of-thumb, they may be fertilized with a low-nitrogen fertilizer or a fertilizer made especially for bulbs as soon as the shoots start to appear in spring. 

For daffodils, the American Daffodil Society recommends reapplying fertilizer at bloom time as well. Other sources recommend fertilizing daffodils and tulips after the bulbs have finished blooming. Regardless of when you fertilize, if you are using a granular fertilizer, avoid getting any on the foliage and be sure to water it in or apply it just before a rain.

Miscanthus sinensis 'Gracillimus'
Image courtesy plants.ces.ncsu.edu

Cut back ornamental grasses early in the month before they start to display new spring growth. Cut to 8” from the ground. If you wait too long, you risk cutting the new, emerging foliage. 

For larger ornamental grasses, such as miscanthus, pruners or hedge trimmers will do the job nicely. If you need to divide the grasses, let me recommend the use of a reciprocating (AKA, Sawzall) saw to do the work. I took day-long division projects down to 90 minutes and saved my back in process.

Prune tree and shrub twigs that were affected by winter kill. Cut back to green wood. If pruning back to a main truck, remember to preserve the branch collar for optimal healing of the area. To determine if a branch is dead or alive, scratch the bark with your fingernail or your pruners.

There will always be other early spring projects. Tackle them as you can. Or, even better, teach the kiddos how to handle some tasks and get them in contact with nature (and, perhaps, earn credit for a science project). 

Gardening should be a good time to be outdoors and mix aesthetics and learning, with a bit of exercise thrown in. Just remember that gardening is, for most, a hobby that should enhance your yards and provide you with a strong dose of self-satisfaction and good cheer. Happy gardening all!

Bruce Bennett

Contributing columnist, Bruce Bennett, is a WSU Master Gardener, lecturer and garden designer. If you have questions concerning this article, have a gardening question or two to ask concerning your landscape or want to suggest a topic for a future column, contact Bruce at gardenguy4u@gmail.com.

Previous columns can be seen here.