Plant tea roses in their own bed. Provide plenty of space between the bushes so air can circulate freely around them. This will help guard against fungal diseases. They need rich, friable soil and more frequent applications of fertilizer than any other flower in the garden. Separating them from other annual and perennial flowers will make caring for them less complicated.
Remove their winter protection in mid spring, as soon as average nighttime temperatures climb a few degrees above freezing. Roses can stand a little frost, so don't worry too much if a late cold snap moves in.
Prune hybrid tea roses in early spring, as soon as the leaf buds begin to open. Remove dead or diseased canes all the way back to healthy wood. Cut out any canes that are growing across another one, as well as any canes that are growing toward the center of the bush. When pruning roses, make the cut just above an outward facing bud (a slight swelling on the stem). These dormant buds will grow into new branches when the rose bush is pruned.
Fertilize your hybrid tea roses in early spring when you remove their winter protection. Sprinkle granulated rose food around the base of the plant, but keep the granules from actually touching the plant. Follow the manufacturer's recommended rate of application. Fertilize again around midsummer (the longest day of the year), and again in the first week of August. If you fertilize after early August the vigorous new growth that results from fertilization will not have enough time to harden up before freezing weather sets in.
Mulch the rose bed. Use cocoa hulls, buckwheat hulls, shredded bark or landscape rock. Mulching roses is important because it keep rainfall from splashing fungal or other rose diseases in the soil onto the stems and leaves of the rose bushes.
Water hybrid tea roses the equivalent of 2 inches of rainfall per week. Do not water using an overhead sprinkler; water on the leaves invites disease and fungus. Use a soaker hose to water at soil level or water hybrid tea roses individually by putting a hose set to a slow trickle near the base of the bush for 60 to 90 minutes.
Inspect regularly for black spot, aphids and powdery mildew. Black spot is indicated by black spots on the leaves. Powdery mildew shows up as a white powder on the leaves and stems. Use anti-fungal products specially formulated for roses and apply them following the manufacturer's directions. Apply these on a calm day so the wind does not apply the chemicals to other plants. Aphids are small white insects that suck the sap from plants. They are apparent by slightly transparent brownish streaks or spots on the leaves where the sap has been removed by the aphids. You can also see them crawling on the plant if you look closely. Treat by spraying with horticultural oil or a strong spray of water from the hose.
Remove faded blossoms promptly. Cut them off below the second or third set of leaves, ideally just above an outward-facing bud.
Provide winter protection. Cut back the canes to about two-thirds of their height in late fall, after the leaves have changed color and dropped off. Mound soil up in a cone shape over the graft union (the lump on the main stem, close to soil level). Surround the rose with a cage of chicken wire about two feet high. Fill the enclosure with fallen autumn leaves. Another method is to use commercially available rose cones. Put these over the bushes after pruning and mounding up soil and leaves. Place a heavy rock on top of the rose cone to keep it from blowing away in high winds.