Tuesday, May 5, 2015

Growing Beautiful Roses

Tips from Ashcombe's Nursery staff

Roses bring many years of enjoyment.  With their colors, fragrances and forms, its no wonder they are 
considered the Queen of the Flowers.  Here are a few of our suggestions for happy, healthy bushes:

LOCATION:  To do their best, roses need a minimum of 5-6 hours of sun daily; 7-8 hours or more is even better.  Good air circulation is essential to help reduce potential problems.  For best results, plant roses in a spot where morning sun will quickly dry dew and moisture off of foliage, for water on rose foliage can result in leaf diseases like blackspot and mildew.

SOIL:  Roses must be planted in soil that is well drained.  If drainage is questionable in the spot you’ve selected for planting, make a raised bed that will elevate your roses to a more favorable drainage position.  Soil should be loamy and not compacted.  To improve compacted soil, incorporate decayed leaves, well rotted manure, natural humus or a soil builder such as ‘Bumper Crop’ into soil and work in to a depth of 1 foot or more.  
Incorporate these materials into your entire rose bed or planting area - not just the planting hole.  When soil is loose, it absorbs water better, drains excess moisture faster and allows plant roots to get oxygen.  Amending soil in the enitre bed - not just the planting hole, encourages roots to grow deeper and wider, thus better 
preparing your roses for drought and other stress.  Ideal soil pH is 6.5.  For pH below 5.5, apply ground 
limestone at the rate of 3 to 5lbs. per 100 square feet.

PLANTING:  Dig your planting hole at least 2-3’ wide and just deep enough that the rose will sit in the hole with its graft or bud union right above the ground level.  Don’t plant too deeply!  If the graft is buried, the rose could die.  Mix 1-2 part organic matter into 3 parts of the soil you’ve removed from the hole.  Place rose to proper depth, then backfill until the hole is 1/3 full.  Firm soil down with your hands, be sure no air pockets are left in soil - for they will dry out roots.  Water enough to fill up the hole and let it drain away to settle soil well before you finish back filling.  After filling hole to top with soil, water again thoroughly.  Making a little trench around the newly planted rose will help hold water near the rose roots until it soaks in.  Use a mulch to conserve soil 
moisture (but do not mound it around the graft at base of rose or you may kill rose).

FERTILIZING:  Newly planted roses should not be fertilized the first year except for a root stimulator used at planting time.  Fertilize established roses after spring pruning and twice after that at about 7 week intervals.  Fertilize no later in the season than August 15 in our area to avoid a late season flush of growth which could be damaged by fall frost.  There are many available fertilizers to use.  In general, the best way to fertilize is to get your soil tested and follow test recommendations.  The alternative is to observe your roses growth pattern.  In general a 5-10-10 fertilizer is good for roses (follow directions on package).

5 (N) - 10 (P) - 10 (K)
5 Nitrogen (N) - promotes green growth, good stems and leaves.  Too much N results in too many 
leaves at the expense of flowers.
10 Phosphorus (P) - promotes good root growth and flower production
10 Potassium (K) - promotes vigorous, strong growth.

Sprinkle fertilizer around rose, cultivate it in only lightly so shallow feeder roots aren’t damaged.  Be sure to 
water in granular fertilizer to activate it.

WATERING:  Never allow your roses to get overly dry but remember that they cannot tolerate soggy or poorly drained wet soil either.  Dig down in soil 2 inches.  If soil is dry, it is time to water.  In dry weather, it is a good idea to soak the ground once a week with a drip or soaker hose.  Do not use sprinkler or overhead watering  do not spray rose foliage with a hose.  (Wet rose foliage is susceptible to fungal diseases).  Water in cool morning or late afternoon hours.  Avoid watering too late in the evening or in the heat of the day.

PRUNING:  Groundcover or bushy types of roses should be pruned in spring when new growth is starting to show.  Push aside winter insulation (see section on winterizing) and prune back canes to 6-10”.  Cut canes 1/4 inch above a bud faces outward so that new shoots will grow outward from these points.  Make cuts at a 45 
degree angle.  Remove all dead, diseases, weak or crossing branches.  Climbing roses (tall roses with long 
flexible stems) should be left to grow for several years with no pruning other than what is necessary to remove weak or damaged wood.  After that, prune 1/3 of old canes out each year so you have older canes to produce flowers and newer stems to produce vigorous growth.  Shorten long stems as needed to keep roses the height you want.  

DEADHEADING:  Many roses on the market today are everblooming or repeat bloomers.  This means that they will produce a flush of late spring flowers, then rest and form buds for a second (or more) or more period of bloom.  To ensure abundant rebloom, many roses benefit at this point from some cosmetic pruning called deadheading!  Cut each rose stem that flowered back to 1/4 inch above a growing point that supports 2 sets of 5 leaflets (multiple leaflets indicate a strong growing site).  Pruning stimulates new growth so new shoots and buds will grow back rapidly at this spot to produce a fresh display of flowers.  Some hedge, shrub and other landscape roses rebloom beautifully with no deadheading but as a general rule, this cosmetic pruning is instrumental in the rebloom of many roses.

PESTS AND DISEASES:  In general, roses can be afflicted by a variety of diseases and pests (mildew, blackspot, aphids in particular), but you should not let this scare you away from a roses’ beauty and fragrance in the garden.  A simple routine of simple controls will take care of rose problems which usually are more unsightly than deadly.  Use a rose spray or dust every 7-10 days to prevent and control problems.  (Spraying is easier 
because you will get good coverage above and below leaf surfaces, which is necessary for good results).  To control fungal leaf diseases and insect pests, start your routine as soon as you see spring growth and continue throughout the summer.  Remember that good cultural practices are stil the best ‘cure’ for rose problems.  Keep vigor high with proper fertilizer and watering, plant in morning sun, don’t crowd roses into spots with poor air flow, keep dead leaves cleaned up and prune aggressively as needed to thin dense plants out and keep roses happy and healthy.

WINTERIZING:  Many roses benefit from a bit of cold weather protection.  To winterize, cover the bud unions of graft with a winter mulch such as peat moss/soil mix (4 parts peat, 1 part soil), pine needles, leaves or 
mushroom soil.    After the first really harde freeze, protect groundcovers or iniature roses with pine needles and an upside down bushel basket.  Wrap canes of climbers in burap or plastic for protection from cold and winter breakage.  Use a plastic collar or bottomless bucket around rose crowns to hold winter mulch in place.  Covering bud union or graft protects it from freezing damage - for this is the vital growing point for spring shoots.  In spring however, as temperatures gradually warm up it is critical that winter mulches be slowly pulled away from this graft.  Failing to unmulch your rose will result in its death.

ROSES AS CUT FLOWERS:  Cut your roses on an angle with sharp pruners or knife.  Cut when the outside petals first start to unfold.  Cut 1/4 inch above a bud or growing point and always leave at least two sets of five leaflets remaining below the flower of the plant.

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